Exhibit 3.1

ALECTOR, INC.

AMENDED AND RESTATED BYLAWS

(initially adopted on September 19, 2017)

(as amended and restated on June 15, 2023)

TABLE OF CONTENTS

TABLE OF CONTENTS

(continued)

-ii-

ALECTOR, INC.

AMENDED AND RESTATED BYLAWS

ARTICLE I—CORPORATE OFFICES

1.1 REGISTERED OFFICE

The registered office of Alector, Inc. shall be fixed in the corporation’s certificate of incorporation, as the same may be amended from time to time.

1.2 OTHER OFFICES

The corporation’s board of directors (the “board of directors”) may at any time establish other offices at any place or places.

ARTICLE II—MEETINGS OF STOCKHOLDERS

2.1 PLACE OF MEETINGS

Meetings of stockholders shall be held at any place, within or outside the State of Delaware, determined by the board of directors. The board of directors may, in its sole discretion, determine that a meeting of stockholders shall not be held at any place, but may instead be held solely by means of remote communication as authorized by Section 211(a)(2) of the Delaware General Corporation Law (the “DGCL”). In the absence of any such designation or determination, stockholders’ meetings shall be held at the corporation’s principal executive office.

2.2 ANNUAL MEETING

The annual meeting of stockholders shall be held at such place, on such day and at such time as may be fixed by the board of directors each year. At the annual meeting, directors shall be elected and any other proper business, brought in accordance with Section 2.4 of these bylaws, may be transacted. The board of directors acting pursuant to a resolution adopted by a majority of the Whole Board (as defined below) may cancel, postpone or reschedule any previously scheduled annual meeting at any time, before or after the notice for such meeting has been sent to the stockholders. For the purposes of these bylaws, the term “Whole Board” shall mean the total number of authorized directorships whether or not there exist any vacancies or other unfilled seats in previously authorized directorships.

2.3 SPECIAL MEETING

(i) A special meeting of the stockholders, other than as required by statute, may be called at any time by (A) the board of directors acting pursuant to a resolution adopted by a majority of the Whole Board, (B) the chairperson of the board of directors, (C) the chief executive officer or (D) the president. A special meeting may not be called by any other person or persons, and any power of stockholders to call a special meeting of stockholders is specifically denied. The board of directors acting pursuant to a resolution adopted by a majority of the Whole Board may cancel, postpone or reschedule any previously scheduled special meeting at any time, before or after the notice for such meeting has been sent to the stockholders.

(ii) The notice of a special meeting shall include the purpose for which the meeting is called. Only such business shall be conducted at a special meeting of stockholders as shall have been brought before the meeting by or at the direction of a majority of the Whole Board, chairperson of the board of directors, the chief executive officer or the president. Nothing contained in this Section 2.3(ii) shall be construed as limiting, fixing or affecting the time when a meeting of stockholders called by action of the board of directors may be held.

2.4 ADVANCE NOTICE PROCEDURES

(i) Advance Notice of Stockholder Business. At an annual meeting of the stockholders, only such business shall be conducted as shall have been properly brought before the meeting. To be properly brought before an annual meeting, business must be brought (A) pursuant to the corporation’s proxy materials with respect to such meeting (or supplement thereto), (B) by or at the direction of the board of directors, or any committee thereof that has been formally delegated authority to propose such business pursuant to a resolution adopted by a majority of the Whole Board, (C) by a stockholder of the corporation who (1) is a stockholder of record at the time of the giving of the notice required by this Section 2.4(i); (2) is a stockholder of record on the record date for the determination of stockholders entitled to notice of the annual meeting; (3) is a stockholder of record on the record date for the determination of stockholders entitled to vote at the annual meeting; (4) is a stockholder of record at the time of the annual meeting; and (5) has timely complied in proper written form with the notice procedures set forth in this Section 2.4(i), or (D) as may be provided in the certificate of designations for any class or series of preferred stock. In addition, for business to be properly brought before an annual meeting by a stockholder, such business must be a proper matter for stockholder action pursuant to these bylaws and applicable law. Except for proposals properly made in accordance with Rule 14a-8 under the Securities Exchange Act of 1934, as amended, or any successor thereto, and the rules and regulations thereunder (as so amended and inclusive of such rules and regulations, the “1934 Act”), and included in the notice of meeting given by or at the direction of the board of directors, for the avoidance of doubt, and unless clause (D) above is applicable, clause (C) above shall be the exclusive means for a stockholder to bring business before an annual meeting of stockholders.

(a) To comply with clause (C) of Section 2.4(i) above, a stockholder’s notice must set forth all information required under this Section 2.4(i) and must be timely received by the secretary of the corporation (the “secretary”). To be timely, a stockholder’s notice must be received by the secretary at the principal executive offices of the corporation not later than 5:00 p.m., Pacific time, on the 45th day nor earlier than 8:00 a.m., Pacific time, on the 75th day before the one-year anniversary of the date on which the corporation first mailed its proxy materials or a notice of availability of proxy materials (whichever is earlier) for the preceding year’s annual meeting; provided, however, that in the event that no annual meeting was held in the previous year or if the date of the annual meeting for the current year is changed by more than 25 days from the one-year anniversary of the date of the previous year’s annual meeting, then, for notice by the stockholder to be timely, it must be so received by the secretary at the then-principal place of business of the corporation not earlier than 5:00 p.m., Pacific time on the 120th day prior to such annual meeting and not later than 5:00 p.m., Pacific time on the later of (i) the 90th day prior to such annual meeting, or (ii) the tenth day following the day on which Public Announcement (as defined below) of the date of such annual meeting is first made. In no event shall any adjournment, rescheduling, postponement or other delay of an annual meeting or the announcement thereof commence a new time period (or extend any time period) for the giving of a

-2-

stockholder’s notice as described in this Section 2.4(i)(a). “Public Announcement” shall mean disclosure in a press release reported by a national news service or in a document publicly filed by the corporation with the Securities and Exchange Commission pursuant to Section 13, 14 or 15(d) of the 1934 Act or by such other means as is reasonably designed to inform the public or stockholders of the corporation in general of such information, including, without limitation, posting on the corporation’s investor relations website.

(b) To be in proper written form, a stockholder’s notice to the secretary must set forth as to each matter of business the stockholder intends to bring before the annual meeting:

(1) a brief description of the business intended to be brought before the annual meeting, including the text of any proposed resolutions and in the event that such business includes a proposal to amend the bylaws of the corporation, the language of the proposed amendment and the reasons for conducting such business at the annual meeting,

(2) the name and address, as they appear on the corporation’s books, of the stockholder proposing such business and any Stockholder Associated Person (as defined below),

(3) the class or series and number of shares of the corporation that are, directly or indirectly, held of record or are beneficially owned by the stockholder or any Stockholder Associated Person and any Derivative Instruments (as defined below) held or beneficially held by the stockholder or any Stockholder Associated Person, including the full notional amount of any securities that, directly or indirectly, underlie any Derivative Instruments,

(4) any (i) agreement, arrangement or understanding (including without limitation and regardless of the form of settlement, any derivative, long or short positions, profit interests, forwards, futures, swaps, options, warrants, convertible securities, stock appreciation or similar rights, hedging transactions and borrowed or loaned shares) that has been entered into by or on behalf of such stockholder or any Stockholder Associated Person with respect to the corporation’s securities (any of the foregoing, a “Derivative Instrument”) including the full notional amount of any securities that, directly or indirectly, underlie any Derivative Instrument); and (ii) other agreement, arrangement or understanding that has been made, the effect or intent of which is to create or mitigate loss to, or to manage the risk or benefit from share price changes for, or to increase or decrease the voting power of, such stockholder or any Stockholder Associated Person with respect to any securities of the corporation,

(5) any material interest of the stockholder or a Stockholder Associated Person in such business,

(6) a representation and undertaking as to whether such stockholder or any Stockholder Associated Person or others acting in concert with them intends, or is part of a group that intends, to (x) deliver a proxy statement or form of proxy to holders of at least the percentage of the voting power of the corporation’s then-outstanding stock required to approve or adopt the proposal (which representation and undertaking must include a statement as to whether such stockholder or any Stockholder Associated Person or others acting in concert with them intends to solicit the requisite percentage of the voting power of the corporation’s stock under Rule 14a-19 of the 1934 Act); or (y) otherwise solicit proxies from stockholders in support of such proposal or nomination,

-3-

(7) all agreements, arrangements and understandings between or among the stockholder and any Stockholder Associated Persons or between or among the stockholder or any Stockholder Associated Person and any other person or entity (including their names) in connection with the proposal of such business by such stockholder,

(8) any proxy, contract, arrangement, understanding or relationship pursuant to which the stockholder or any Stockholder Associated Person has a right to vote any shares of any security of the corporation,

(9) any rights to dividends on the corporation’s securities owned beneficially by such stockholder or any Stockholder Associated Person that are separated or separable from the underlying security,

(10) any proportionate interest in the corporation’s securities or any Derivative Instruments held, directly or indirectly, by a general or limited partnership in which such stockholder or any Stockholder Associated Person is a general partner or, directly or indirectly, beneficially owns an interest in a general partner of such general or limited partnership,

(11) any performance-related fees (other than an asset-based fee) that such stockholder or any Stockholder Associated Person is entitled to based on any increase or decrease in the value of the corporation’s securities or Derivative Instruments, including, without limitation, any such interests held by members of the immediate family of such persons sharing the same household,

(12) any significant equity interests or any Derivative Instruments in any principal competitor of the corporation that are held by such stockholder or any Stockholder Associated Person,

(13) any direct or indirect interest of such stockholder or any Stockholder Associated Person in any contract with the corporation, any affiliate of the corporation or any principal competitor of the corporation (in each case, including, without limitation, any employment agreement, collective bargaining agreement or consulting agreement),

(14) any material pending or threatened legal proceeding in which such stockholder or any Stockholder Associated Person is a party or material participant involving the corporation or any of its officers, directors or affiliates,

(15) any material relationship between such stockholder or any Stockholder Associated Person, on the one hand, and the corporation or any of its officers, directors or affiliates, on the other hand,

(16) a representation and undertaking that the stockholder is a holder of record of stock of the corporation as of the date of submission of the stockholder’s notice and intends to appear in person or by proxy at the annual meeting to bring such other business before the annual meeting,

(17) any other information relating to such stockholder or any Stockholder Associated Person or others acting in concert with them, or director nominee or proposed business, that, in each case, would be required to be disclosed in a proxy statement or other filing required to be made in connection with the solicitation of proxies in support of such nominee (in a contested election of directors) or proposal pursuant to Section 14 of the 1934 Act, and

-4-

(18) such other information relating to any proposed item of business as the corporation may reasonably require to determine whether such proposed item of business is a proper matter for stockholder action

(such information provided and statements made as required by clauses (1) through (18), a “Business Solicitation Statement”). In addition, to be timely and in proper written form, a stockholder’s notice to the secretary (and any additional information submitted to the corporation in connection therewith) must further be updated and supplemented, (x) if necessary, so that the information provided or required to be provided in such notice is true and correct as of the record date(s) for determining stockholders entitled to notice of, and to vote at, the meeting and as of the date that is 10 business days prior to the meeting or any adjournment, rescheduling, postponement or other delay thereof; and (y) to provide any additional information that the corporation may reasonably request. Any such update and supplement or additional information (including if requested pursuant to Section 2.4(i)(b)(18)) must be received by the secretary at the principal executive offices of the corporation (A) in the case of a request for additional information, promptly following a request therefor, which response must be received by the secretary not later than such reasonable time as is specified in any such request from the corporation; or (B) in the case of any other update or supplement of any information, not later than five business days after the record date(s) for the meeting (in the case of any update and supplement required to be made as of the record date(s)), and not later than eight business days prior to the date of the meeting or any adjournment, rescheduling, postponement or other delay thereof (in the case of any update or supplement required to be made as of 10 business days prior to the meeting or any adjournment, rescheduling, postponement or other delay thereof). The failure to timely provide such update, supplement or additional information shall result in the proposal no longer being eligible for consideration at the annual meeting. For purposes of this Section 2.4, a “Stockholder Associated Person” of any stockholder shall mean (i) any person controlling, directly or indirectly, or acting in concert with, such stockholder, (ii) any beneficial owner of shares of stock of the corporation owned of record or beneficially by such stockholder and on whose behalf the proposal or nomination, as the case may be, is being made, or (iii) any person controlling, controlled by or under common control with such person referred to in the preceding clauses (i) and (ii).

(c) Without exception, no business shall be conducted at any annual meeting except in accordance with the provisions set forth in this Section 2.4(i) and, if applicable, Section 2.4(ii). In addition, business proposed to be brought by a stockholder may not be brought before the annual meeting if such stockholder or a Stockholder Associated Person, as applicable, takes action contrary to the representations made in the Business Solicitation Statement applicable to such business or if the Business Solicitation Statement applicable to such business contains an untrue statement of a material fact or omits to state a material fact necessary to make the statements therein not misleading. Notwithstanding anything to the contrary in this Section 2.4, unless otherwise required by law, if the stockholder (or a qualified representative of the stockholder) does not appear in person at the meeting to present proposed business, such proposed business will not be transacted, notwithstanding that proxies in respect of such business may have been received by the corporation and counted for purposes of determining a quorum. For purposes of this Section 2.4, to be considered a qualified representative of the stockholder, a person must be a duly authorized officer, manager or partner of such stockholder or must be authorized by a writing executed by such stockholder or an electronic transmission delivered by such stockholder to act for such stockholder as proxy at the meeting, and such person must produce such writing or electronic transmission, or a reliable reproduction of the writing or electronic transmission, at the meeting. The chairperson of the annual meeting shall, if the facts warrant, determine and declare at the annual meeting that business was not properly brought before the annual meeting and in accordance with the provisions of this Section 2.4(i), and, if the chairperson should so determine, the chairperson shall so declare at the annual meeting that any such business not properly brought before the annual meeting shall not be conducted.

-5-

(ii) Advance Notice of Director Nominations at Annual Meetings. Notwithstanding anything in these bylaws to the contrary, only persons who are nominated in accordance with the procedures set forth in this Section 2.4(ii) shall be eligible for election or re-election as directors at an annual meeting of stockholders. Nominations of persons for election to the board of directors of the corporation shall be made at an annual meeting of stockholders only (A) by or at the direction of the board of directors, or any committee thereof that has been formally delegated authority to nominate such persons pursuant to a resolution adopted by a majority of the Whole Board, or (B) by a stockholder of the corporation who (1) was a stockholder of record at the time of the giving of the notice required by this Section 2.4(ii); (2) is a stockholder of record on the record date for the determination of stockholders entitled to notice of the annual meeting; (3) is a stockholder of record on the record date for the determination of stockholders entitled to vote at the annual meeting; (4) is a stockholder of record at the time of the annual meeting; and (5) has complied with the notice procedures set forth in this Section 2.4(ii). In addition to any other applicable requirements, for a nomination to be made by a stockholder, the stockholder must have given timely notice thereof in proper written form to the secretary at the corporation’s principal executive offices.

(a) To comply with clause (B) of Section 2.4(ii) above, a nomination to be made by a stockholder must set forth all information required under this Section 2.4(ii) and must be received by the secretary at the principal executive offices of the corporation at the time set forth in, and in accordance with, the final three sentences of Section 2.4(i)(a) above. In no event may a stockholder provide notice with respect to a greater number of director candidates than there are director seats subject to election by stockholders at the annual meeting. If the number of directors to be elected to the board of directors is increased and there is no Public Announcement naming all of the nominees for director or specifying the size of the increased board of directors at least 10 days before the last day that a stockholder may deliver a notice of nomination pursuant to the foregoing provisions, then a stockholder’s notice required by this Section 2.4(ii) will also be considered timely, but only with respect to any nominees for any new positions created by such increase, if it is received by the secretary at the principal executive offices of the corporation no later than 5:00 p.m., Pacific Time, on the 10th day following the day on which such Public Announcement is first made.

(b) To be in proper written form, such stockholder’s notice to the secretary must set forth:

(1) as to each person (a “nominee”) whom the stockholder proposes to nominate for election or re-election as a director: (A) the name, age, business address and residence address of the nominee, (B) the principal occupation or employment of the nominee, (C) the class and number of shares of the corporation that are held of record or are beneficially owned by the nominee and any Derivative Instruments held or beneficially held by the nominee, including the full notional amount of any securities that, directly or indirectly, underlie any such Derivative Instruments, (D) whether and the extent to which any hedging or other transaction or series of transactions has been entered into by or on behalf of the nominee with respect to any securities of the corporation, and a description of any other agreement, arrangement or understanding (including any short position or any borrowing or lending of shares), the effect or intent of which is to create or mitigate loss to, or to manage the risk or benefit of share price changes for, or to increase or decrease the voting power of the nominee, (E) all arrangements or understandings between the stockholder giving the notice and any Stockholder Associated Person, on the one hand, and each nominee and such nominee’s respective affiliates and associates, or others acting in concert with them, on the other hand, including, without limitation, all information that would be required to be disclosed pursuant to Item 404 under Regulation S-K if such stockholder, beneficial owner, affiliate or associate were the “registrant” for purposes of such rule and such person were a director or executive officer of such registrant, (F) a written statement executed by the nominee acknowledging that as a director of the corporation, the nominee will owe a fiduciary

-6-

duty under Delaware law with respect to the corporation and its stockholders, (G) any proxy, contract, arrangement, understanding or relationship pursuant to which such stockholder or any Stockholder Associated Person or others acting in concert with them has a right to vote any shares of any security of the corporation, (H) any material pending or threatened legal proceeding in which such stockholder or any Stockholder Associated Person is a party or material participant involving the corporation or any of its officers, directors or affiliates, (I) any material relationship between such stockholder or any Stockholder Associated Person or others acting in concert with them, on the one hand, and the corporation or any of its officers, directors or affiliates, on the other hand, (J) any direct or indirect compensatory, payment, indemnification or other financial agreement, arrangement or understanding that such nominee has, or has had within the past three years, with any person or entity other than the corporation (including, without limitation, the amount of any payment or payments received or receivable thereunder), in each case in connection with candidacy or service as a director of the corporation (such agreement, arrangement or understanding, a “Third-Party Compensation Arrangement”), and (K) any other information relating to the nominee that would be required to be disclosed about such nominee if proxies were being solicited for the election or re-election of the nominee as a director, or that is otherwise required, in each case pursuant to Regulation 14A under the 1934 Act (including without limitation the nominee’s written consent (i) to being named as a nominee of such stockholder, (ii) to being named in the corporation’s form of proxy pursuant to Rule 14a-19 under the 1934 Act and (iii) to serving as a director of the corporation if elected); and

(2) as to such stockholder giving notice, (A) the information required to be provided pursuant to clauses (2) through (18) of Section 2.4(i)(b) above, and the update and supplement referenced in Section 2.4(i)(b) above (except that the references to “business” in such clauses shall instead refer to nominations of directors for purposes of this paragraph), and (B) a representation and undertaking as to whether either such stockholder or Stockholder Associated Person will (x) deliver a proxy statement and form of proxy to holders of a number of the corporation’s voting shares reasonably believed by such stockholder or Stockholder Associated Person to be necessary to elect or re-elect such nominee(s) (which representation must include a statement as to whether such stockholder or Stockholder Associated Person or others acting in concert with them intends to solicit the requisite percentage of the voting power of the corporation’s stock under Rule 14a-19 of the 1934 Act) and intends to appear in person or by proxy at the meeting to bring such nomination before the meeting, or (y) otherwise solicit proxies from stockholders in support of such nomination (such information provided and statements made as required by clauses (A) and (B) above, a “Nominee Solicitation Statement”).

(c) No later than five business days prior to the annual meeting or any adjournment, rescheduling, postponement or other delay thereof, a stockholder nominating one or more individuals for election as a director will provide the corporation with reasonable evidence that such stockholder has met the requirements of Rule 14a-19. The failure to timely provide such update, supplement, evidence or additional information shall result in the nomination no longer being eligible for consideration at the annual meeting. If the stockholder fails to comply with the requirements of Rule 14a-19 (including because the stockholder fails to provide the corporation with all information or notices required by Rule 14a-19), then the director nominees proposed by such stockholder shall be ineligible for election at the annual meeting and any votes or proxies in respect of such nomination shall be disregarded, notwithstanding that such proxies may have been received by the corporation and counted for the purposes of determining quorum. For the avoidance of doubt, the obligation to update and supplement, or provide additional information or evidence, with respect to any nomination as set forth in these bylaws shall not limit the corporation’s rights with respect to any deficiencies in any notice provided by a stockholder, extend any applicable deadlines pursuant to these bylaws or enable or be deemed to permit a stockholder who has previously submitted notice pursuant to these bylaws to amend or update any nomination or proposal or to submit any new nomination or proposal. No disclosure

-7-

pursuant to these bylaws will be required with respect to the ordinary course business activities of any broker, dealer, commercial bank, trust company or other nominee who is the stockholder submitting a notice pursuant to this Section 2.4 solely because such broker, dealer, commercial bank, trust company or other nominee has been directed to prepare and submit the notice required by these bylaws on behalf of a beneficial owner.

(d) To be eligible to be a nominee of any stockholder for election or re-election as a director of the corporation, at the request of the board of directors, any person nominated by a stockholder for election or re-election as a director must furnish to the secretary (1) that information required to be set forth in the stockholder’s notice of nomination of such person as a director as of a date subsequent to the date on which the notice of such person’s nomination was given and (2) such other information as may reasonably be required by the corporation to determine the eligibility of such proposed nominee to serve as an independent director or audit committee financial expert of the corporation under applicable law, securities exchange rule or regulation, or any publicly disclosed corporate governance guideline or committee charter of the corporation and that could be material to a reasonable stockholder’s understanding of the independence, or lack thereof, or the qualifications of such nominee. Such additional information, if applicable, must be received by the secretary at the principal executive offices of the corporation promptly following a request therefor, not later than such reasonable time as is specified in any such request from the corporation. In the absence of the timely furnishing of such requested information, such stockholder’s nomination shall not be considered in proper form and shall be ineligible for consideration at the annual meeting pursuant to this Section 2.4(ii). Without limiting the foregoing, to be eligible to be a nominee and qualify for election or re-election as a director of the corporation, such nominee must deliver (in accordance with the time period prescribed for delivery in a notice to such nominee given by or on behalf of the board of directors), to the secretary at the principal executive offices of the corporation, (1) a signed and completed written questionnaire (in a form provided by the corporation, which will be provided by the secretary within 10 days of receiving such request) containing information regarding such nominee’s background and qualifications and such other information as may reasonably be required by the corporation to determine the eligibility of such nominee to serve as a director of the corporation or to serve as an independent director of the corporation and (2) a written representation and undertaking that such nominee (A) unless previously disclosed to the corporation, is not and, if elected as a director during such director’s term of office will not become, a party to (x) any agreement, arrangement or understanding with, and has not given and will not give any commitment or assurance to, any person or entity as to how such nominee, if elected as a director of the corporation, will act or vote on any issue or question or (y) any Third-Party Compensation Arrangement, unless previously disclosed to the corporation, and (B) if elected as a director of the corporation, such nominee would be in compliance, and will continue to comply, with all applicable corporate governance, conflict of interest, confidentiality, stock ownership and trading and other policies and guidelines of the corporation applicable to directors and in effect during such person’s term in office as a director (and, if requested by any nominee, the secretary shall provide to such nominee all such policies and guidelines then in effect), and that such nominee intends to serve a full term on the board of directors. No later than five business days prior to the annual meeting or any adjournment, rescheduling, postponement or other delay thereof, a stockholder nominating individuals for election or re-election as a director will provide the corporation with reasonable evidence that such stockholder has met the requirements of Rule 14a-19. The failure to timely provide such update, supplement, evidence or additional information shall result in the nomination no longer being eligible for consideration at the meeting.

(e) Without exception, no person shall be eligible for election or re-election as a director of the corporation at an annual meeting of stockholders unless nominated in accordance with the provisions set forth in this Section 2.4(ii). In addition, a nominee shall not be eligible for election or re-election if a stockholder or Stockholder Associated Person, as applicable, takes action contrary to the representations made in the Nominee Solicitation Statement applicable to such nominee or if the Nominee Solicitation

-8-

Statement applicable to such nominee or other information provided to the corporation by or on behalf of such nominee contains an untrue statement of a material fact or omits to state a material fact necessary to make the statements therein not misleading. The chairperson of the annual meeting shall, if the facts warrant, determine and declare at the annual meeting that a nomination was not made in accordance with the provisions prescribed by these bylaws, and if the chairperson should so determine, the chairperson shall so declare at the annual meeting, and the defective nomination shall be disregarded. Notwithstanding anything to the contrary in this Section 2.4, unless otherwise required by law, if the stockholder (or a qualified representative of the stockholder) does not appear in person at the meeting to present a nomination, such nomination will be disregarded notwithstanding that proxies in respect of such nomination may have been received by the corporation and counted for purposes of determining a quorum.

(iii) Advance Notice of Director Nominations for Special Meetings.

(a) For a special meeting of stockholders at which directors are to be elected or re-elected pursuant to Section 2.3, nominations of persons for election to the board of directors shall be made only (1) by or at the direction of the board of directors, or any committee thereof that has been formally delegated authority to nominate such persons pursuant to a resolution adopted by a majority of the Whole Board, or (2) by any stockholder of the corporation who (A) is a stockholder of record at the time of the giving of the notice required by this Section 2.4(iii); (B) is a stockholder of record on the record date for the determination of stockholders entitled to notice of the special meeting; (C) is a stockholder of record on the record date for the determination of stockholders entitled to vote at the special meeting; (D) is a stockholder of record at the time of the special meeting; and (E) delivers a timely written notice of the nomination to the secretary that includes the information set forth in Sections 2.4(ii)(b) and (ii)(c) above (with references therein to “annual meeting” deemed to mean “special meeting” for the purposes of this Section 2.4(iii) and further with such procedures that the corporation deems to be applicable to such special meeting). To be timely, such notice must be received by the secretary at the principal executive offices of the corporation not earlier than 8:00 a.m., Pacific time, on the 120th day prior to the day of the special meeting and not later than 5:00 p.m., Pacific time, on the later of (i) the 90th day prior to such special meeting or (ii) the tenth day following the day on which Public Announcement is first made of the date of the special meeting and of the nominees proposed by the board of directors to be elected or re-elected at such meeting. In no event shall any adjournment, rescheduling, postponement or other delay of a special meeting or the announcement thereof commence a new time period for the giving of a stockholder’s notice. A person shall not be eligible for election or re-election as a director at a special meeting unless the person is nominated (i) by or at the direction of the board of directors, or any committee thereof that has been formally delegated authority to nominate such persons pursuant to a resolution adopted by a majority of the Whole Board, or (ii) by a stockholder in accordance with the notice procedures set forth in this Section 2.4(iii). In addition, a nominee shall not be eligible for election or re-election if a stockholder or Stockholder Associated Person, as applicable, takes action contrary to the representations made in the Nominee Solicitation Statement applicable to such nominee or other information provided to the corporation by or on behalf of such nominee or if the Nominee Solicitation Statement applicable to such nominee contains an untrue statement of a material fact or omits to state a material fact necessary to make the statements therein not misleading. Any person nominated in accordance with this Section 2.4(iii) is subject to, and must comply with, the provisions of Section 2.4(ii)(c).

(b) The chairperson of the special meeting shall, if the facts warrant, determine and declare at the meeting that a nomination or business was not made in accordance with the procedures prescribed by these bylaws, and if the chairperson should so determine, the chairperson shall so declare at the meeting, and the defective nomination or business shall be disregarded.

-9-

(iv) Other Requirements and Rights. In addition to the foregoing provisions of this Section 2.4, a stockholder must also comply with all applicable requirements of state law and of the 1934 Act and the rules and regulations thereunder with respect to the matters set forth in this Section 2.4. Nothing in this Section 2.4 shall be deemed to affect any rights of:

(a) a stockholder to request inclusion of proposals in the corporation’s proxy statement pursuant to Rule 14a-8 (or any successor provision) under the 1934 Act; or

(b) the corporation to omit a proposal from the corporation’s proxy statement pursuant to Rule 14a-8 (or any successor provision) under the 1934 Act.

2.5 NOTICE OF STOCKHOLDERS’ MEETINGS

Whenever stockholders are required or permitted to take any action at a meeting, a notice of the meeting shall be given in accordance with Section 232 of the DGCL, and such notice shall state the place, if any, date and hour of the meeting, the means of remote communications, if any, by which stockholders and proxy holders may be deemed to be present in person and vote at such meeting, the record date for determining the stockholders entitled to vote at the meeting, if such date is different from the record date for determining stockholders entitled to notice of the meeting, and, in the case of a special meeting, the purpose or purposes for which the meeting is called. Except as otherwise provided in the DGCL, the certificate of incorporation or these bylaws, the notice of any meeting of stockholders shall be given not less than 10 nor more than 60 days before the date of the meeting to each stockholder entitled to vote at such meeting as of the record date for determining the stockholders entitled to notice of the meeting.

2.6 QUORUM

The holders of a majority of the voting power of the capital stock of the corporation issued and outstanding and entitled to vote, present in person or represented by proxy, shall constitute a quorum for the transaction of business at all meetings of the stockholders, unless otherwise required by law, the certificate of incorporation, these bylaws or the rules of any applicable stock exchange on which the corporation’s securities are listed. Where a separate vote by a class or series or classes or series is required, a majority of the voting power of the outstanding shares of such class or series or classes or series, present in person or represented by proxy, shall constitute a quorum entitled to take action with respect to that vote on that matter, except as otherwise required by law, the certificate of incorporation, these bylaws or the rules of any applicable stock exchange on which the corporation’s securities are listed.

If, however, such quorum is not present or represented at any meeting of the stockholders, then either (i) the chairperson of the meeting, or (ii) the stockholders entitled to vote at the meeting, present in person or represented by proxy, shall have power to adjourn the meeting from time to time, without notice other than announcement at the meeting, until a quorum is present or represented. At such adjourned meeting at which a quorum is present or represented, any business may be transacted that might have been transacted at the meeting as originally noticed.

2.7 ADJOURNED MEETING; NOTICE

When a meeting is adjourned to another time or place (including an adjournment taken to address a technical failure to convene or continue a meeting using remote communication), unless these bylaws otherwise require, notice need not be given of the adjourned meeting if the time, place, if any, thereof, and the means of

-10-

remote communications, if any, by which stockholders and proxy holders may be deemed to be present in person and vote at such adjourned meeting are (i) announced at the meeting at which the adjournment is taken, (ii) displayed, during the time scheduled for the meeting, on the same electronic network used to enable stockholders and proxy holders to participate in that meeting by means of remote communication or (iii) set forth in the notice of meeting given in accordance with Section 222(a) of the DGCL. At the adjourned meeting, the corporation may transact any business which might have been transacted at the original meeting. If the adjournment is for more than 30 days, a notice of the adjourned meeting shall be given to each stockholder of record entitled to vote at the meeting. If after the adjournment a new record date for stockholders entitled to vote is fixed for the adjourned meeting, the board of directors shall fix a new record date for notice of such adjourned meeting in accordance with Section 213(a) of the DGCL and Section 2.11 of these bylaws, and shall give notice of the adjourned meeting to each stockholder of record entitled to vote at such adjourned meeting as of the record date fixed for notice of such adjourned meeting.

2.8 CONDUCT OF BUSINESS

The chairperson of any meeting of stockholders shall determine the order of business and the procedure at the meeting, including such regulation of the manner of voting and the conduct of business and discussion as the chairperson considers to be in order. The chairperson of any meeting of stockholders shall be designated by the board of directors; in the absence of such designation, the chairperson of the board, if any, or the chief executive officer (in the absence of the chairperson) or the president (in the absence of the chairperson of the board of directors and the chief executive officer), or in their absence any other executive officer of the corporation, shall serve as chairperson of the stockholder meeting. The chairperson of any meeting of the stockholders shall have the power to adjourn the meeting to another place, if any, date or time, whether or not a quorum is present.

2.9 VOTING

The stockholders entitled to vote at any meeting of stockholders shall be determined in accordance with the provisions of Section 2.11 of these bylaws, subject to Section 217 (relating to voting rights of fiduciaries, pledgors and joint owners of stock) and Section 218 (relating to voting trusts and other voting agreements) of the DGCL.

Except as may be otherwise provided in the certificate of incorporation, each stockholder shall be entitled to one vote for each share of capital stock held by such stockholder as of the applicable record date that has voting power upon the matter in question.

Except as otherwise provided by law, the certificate of incorporation, these bylaws or the rules of any applicable stock exchange on which the corporation’s securities are listed, in all matters other than the election of directors, the affirmative vote of a majority of the voting power of the shares present in person or represented by proxy at the meeting and entitled to vote on the subject matter shall be the act of the stockholders. Except as otherwise required by law, the certificate of incorporation or these bylaws, directors shall be elected by a plurality of the voting power of the shares present in person or represented by proxy at the meeting and entitled to vote on the election of directors. Where a separate vote by a class or series or classes or series is required, in all matters other than the election of directors, the affirmative vote of the majority of the voting power of the shares of such class or series or classes or series present in person or represented by proxy at the meeting and entitled to vote on the subject matter shall be the act of such class or series or classes or series, except as otherwise provided by law, the certificate of incorporation, these bylaws or the rules of any applicable stock exchange on which the corporation’s securities are listed.

-11-

2.10 STOCKHOLDER ACTION BY WRITTEN CONSENT WITHOUT A MEETING

Unless otherwise provided in the certificate of incorporation and subject to the rights of the holders of the shares of any series of preferred stock or any other class of stock or series thereof having a preference over the common stock as dividend or upon liquidation of the corporation, any action required or permitted to be taken by the stockholders of the corporation must be effected at a duly called annual or special meeting of stockholders of the corporation and may not be effected by any consent in writing by such stockholders.

2.11 RECORD DATES

In order that the corporation may determine the stockholders entitled to notice of any meeting of stockholders or any adjournment thereof, the board of directors may fix a record date, which record date shall not precede the date upon which the resolution fixing the record date is adopted by the board of directors and which record date shall not be more than 60 nor less than 10 days before the date of such meeting. If the board of directors so fixes a date, such date shall also be the record date for determining the stockholders entitled to vote at such meeting unless the board of directors determines, at the time it fixes such record date, that a later date on or before the date of the meeting shall be the date for making such determination.

If no record date is fixed by the board of directors, the record date for determining stockholders entitled to notice of and to vote at a meeting of stockholders shall be at the close of business on the day next preceding the day on which notice is given, or, if notice is waived, at the close of business on the day next preceding the day on which the meeting is held.

A determination of stockholders of record entitled to notice of or to vote at a meeting of stockholders shall apply to any adjournment of the meeting; provided, however, that the board of directors may fix a new record date for determination of stockholders entitled to vote at the adjourned meeting, and in such case shall also fix as the record date for stockholders entitled to notice of such adjourned meeting the same or an earlier date as that fixed for determination of stockholders entitled to vote in accordance with the provisions of Section 213 of the DGCL and this Section 2.11 at the adjourned meeting.

In order that the corporation may determine the stockholders entitled to receive payment of any dividend or other distribution or allotment of any rights or the stockholders entitled to exercise any rights in respect of any change, conversion or exchange of stock, or for the purpose of any other lawful action, the board of directors may fix a record date, which record date shall not precede the date upon which the resolution fixing the record date is adopted, and which record date shall be not more than 60 days prior to such action. If no record date is fixed, the record date for determining stockholders for any such purpose shall be at the close of business on the day on which the board of directors adopts the resolution relating thereto.

2.12 PROXIES

Each stockholder entitled to vote at a meeting of stockholders, or such stockholder’s authorized officer, director, employee or agent, may authorize another person or persons to act for such stockholder by proxy authorized by a document or by a transmission permitted by law filed in accordance with the procedure established for the meeting, but no such proxy shall be voted or acted upon after three years from its date, unless the proxy provides for a longer period. The authorization of a person to act as a proxy may be documented, signed and delivered in accordance with Section 116 of the DGCL; provided that such authorization shall set forth, or be delivered with information enabling the corporation to determine, the identity of the stockholder granting such authorization. The revocability of a proxy that states on its face that it is irrevocable shall be governed by the provisions of Section 212 of the DGCL.

-12-

2.13 LIST OF STOCKHOLDERS ENTITLED TO VOTE

The corporation shall prepare, no later than the tenth day before every meeting of stockholders, a complete list of the stockholders entitled to vote at the meeting; provided, however, if the record date for determining the stockholders entitled to vote is less than 10 days before the meeting date, then the list shall reflect the stockholders entitled to vote as of the tenth day before the meeting date, arranged in alphabetical order, and showing the address of each stockholder and the number of shares registered in the name of each stockholder. The corporation shall not be required to include electronic mail addresses or other electronic contact information on such list. Such list shall be open to the examination of any stockholder for any purpose germane to the meeting for a period of 10 days ending on the day before the meeting date: (i) on a reasonably accessible electronic network, provided that the information required to gain access to such list is provided with the notice of the meeting, or (ii) during ordinary business hours, at the corporation’s principal place of business. In the event that the corporation determines to make the list available on an electronic network, the corporation may take reasonable steps to ensure that such information is available only to stockholders of the corporation.

2.14 INSPECTORS OF ELECTION

Before any meeting of stockholders, the corporation shall appoint an inspector or inspectors of election to act at the meeting or its adjournment. The corporation may designate one or more persons as alternate inspectors to replace any inspector who fails to act.

Such inspectors shall:

(i) ascertain the number of shares outstanding and the voting power of each;

(ii) determine the shares represented at the meeting and the validity of proxies and ballots;

(iii) count all votes and ballots;

(iv) determine and retain for a reasonable period a record of the disposition of any challenges made to any determination by the inspectors; and

(v) certify their determination of the number of shares represented at the meeting, and their count of all votes and ballots.

The inspectors of election shall perform their duties impartially, in good faith, to the best of their ability and as expeditiously as is practical. If there are multiple inspectors of election, the decision, act or certificate of a majority is effective in all respects as the decision, act or certificate of all. Any report or certificate made by the inspectors of election is prima facie evidence of the facts stated therein.

-13-

ARTICLE III—DIRECTORS

3.1 POWERS

The business and affairs of the corporation shall be managed by or under the direction of the board of directors, except as may be otherwise provided in the DGCL or the certificate of incorporation.

3.2 NUMBER OF DIRECTORS

The board of directors shall consist of one or more members, each of whom shall be a natural person. Unless the certificate of incorporation fixes the number of directors, the number of directors shall be determined from time to time by resolution of a majority of the Whole Board. No reduction of the authorized number of directors shall have the effect of removing any director before that director’s term of office expires.

3.3 ELECTION, QUALIFICATION AND TERM OF OFFICE OF DIRECTORS

Except as provided in Section 3.4 of these bylaws, each director, including a director elected to fill a vacancy or newly created directorship, shall hold office until the expiration of the term for which elected and until such director’s successor is elected and qualified or until such director’s earlier death, resignation or removal. Directors need not be stockholders unless so required by the certificate of incorporation or these bylaws. The certificate of incorporation or these bylaws may prescribe other qualifications for directors.

If so provided in the certificate of incorporation, the directors of the corporation shall be divided into three classes.

3.4 RESIGNATION AND VACANCIES

Any director may resign at any time upon notice given in writing or by electronic transmission to the corporation. A resignation is effective when the resignation is delivered unless the resignation specifies a later effective date or an effective date determined upon the happening of an event or events. A resignation which is conditioned upon the director failing to receive a specified vote for reelection as a director may provide that it is irrevocable. Unless otherwise provided in the certificate of incorporation or these bylaws, when one or more directors resign from the board of directors, effective at a future date, a majority of the directors then in office, including those who have so resigned, shall have power to fill such vacancy or vacancies, the vote thereon to take effect when such resignation or resignations shall become effective.

Unless otherwise provided in the certificate of incorporation or these bylaws or permitted in the specific case by resolution of the board of directors, and subject to the rights of holders of the shares of any series of preferred stock or any other class of stock or series thereof having a preference over the common stock as dividend or upon liquidation of the corporation, vacancies and newly created directorships resulting from any increase in the authorized number of directors elected by all of the stockholders having the right to vote as a single class may be filled by a majority of the directors then in office, although less than a quorum, or by a sole remaining director, and not by stockholders. If the directors are divided into classes, a person chosen to fill a vacancy or newly created directorship shall hold office until the next election of the class for which such director shall have been chosen and until such person’s successor shall have been duly elected and qualified.

-14-

If at any time, by reason of death or resignation or other cause, the corporation should have no directors in office, then any officer or any stockholder or an executor, administrator, trustee or guardian of a stockholder, or other fiduciary entrusted with like responsibility for the person or estate of a stockholder, may call a special meeting of stockholders in accordance with the provisions of the certificate of incorporation or these bylaws, or may apply to the Court of Chancery for a decree summarily ordering an election as provided in Section 211 of the DGCL.

If, at the time of filling any vacancy or any newly created directorship, the directors then in office constitute less than a majority of the Whole Board (as constituted immediately prior to any such increase), the Court of Chancery may, upon application of any stockholder or stockholders holding at least 10% of the voting stock at the time outstanding having the right to vote for such directors, summarily order an election to be held to fill any such vacancies or newly created directorships, or to replace the directors chosen by the directors then in office as aforesaid, which election shall be governed by the provisions of Section 211 of the DGCL as far as applicable.

3.5 PLACE OF MEETINGS; MEETINGS BY TELEPHONE

The board of directors may hold meetings, both regular and special, either within or outside the State of Delaware.

Unless otherwise restricted by the certificate of incorporation or these bylaws, members of the board of directors, or any committee designated by the board of directors or any subcommittee, may participate in a meeting of the board of directors, or any such committee or subcommittee, by means of conference telephone or other communications equipment by means of which all persons participating in the meeting can hear each other, and such participation in a meeting shall constitute presence in person at the meeting.

3.6 REGULAR MEETINGS

Regular meetings of the board of directors may be held without notice at such time and at such place as shall from time to time be determined by the board of directors.

3.7 SPECIAL MEETINGS; NOTICE

Special meetings of the board of directors for any purpose or purposes may be called at any time by the chairperson of the board of directors, the chief executive officer, the president, the secretary or a majority of the Whole Board; provided that the person(s) authorized to call a special meeting of the board of directors may authorize another person or persons to send notice of such meeting.

Notice of the time and place of special meetings shall be:

(i) delivered personally by hand, by courier or by telephone;

(ii) sent by United States first-class mail, postage prepaid;

(iii) sent by facsimile;

(iv) sent by electronic mail; or

(v) otherwise given by electronic transmission (as defined in Section 232 of the DGCL),

-15-

directed to each director at that director’s address, telephone number, facsimile number, electronic mail address or other contact for notice by electronic transmission, as the case may be, as shown on the corporation’s records.

If the notice is (i) delivered personally by hand, by courier or by telephone, (ii) sent by facsimile, (iii) sent by electronic mail or (iv) otherwise given by electronic transmission, it shall be delivered, sent or otherwise directed to each director, as applicable, at least 24 hours before the time of the holding of the meeting. If the notice is sent by United States mail, it shall be deposited in the United States mail at least four days before the time of the holding of the meeting. Any oral notice of the time and place of the meeting may be communicated to the director in lieu of written notice if such notice is communicated at least 24 hours before the time of the holding of the meeting. The notice need not specify the place of the meeting (if the meeting is to be held at the corporation’s principal executive office) nor the purpose of the meeting.

3.8 QUORUM; VOTING

At all meetings of the board of directors, a majority of the Whole Board shall constitute a quorum for the transaction of business. If a quorum is not present at any meeting of the board of directors, then the directors present thereat may adjourn the meeting from time to time, without notice other than announcement at the meeting, until a quorum is present.

The affirmative vote of a majority of the directors present at any meeting at which a quorum is present shall be the act of the board of directors, except as may be otherwise specifically provided by statute, the certificate of incorporation or these bylaws.

If the certificate of incorporation provides that one or more directors shall have more or less than one vote per director on any matter, every reference in these bylaws to a majority or other proportion of the directors shall refer to a majority or other proportion of the votes of the directors.

3.9 BOARD ACTION BY WRITTEN CONSENT WITHOUT A MEETING

Unless otherwise restricted by the certificate of incorporation or these bylaws, (i) any action required or permitted to be taken at any meeting of the board of directors, or of any committee or subcommittee thereof, may be taken without a meeting if all members of the board of directors or committee or subcommittee, as the case may be, consent thereto in writing or by electronic transmission and (ii) a consent may be documented, signed and delivered in any manner permitted by Section 116 of the DGCL. Any person (whether or not then a director) may provide, whether through instruction to an agent or otherwise, that a consent to action will be effective at a future time (including a time determined upon the happening of an event), no later than 60 days after such instruction is given or such provision is made and such consent shall be deemed to have been given for purposes of this Section 3.9 at such effective time so long as such person is then a director and did not revoke the consent prior to such time. Any such consent shall be revocable prior to its becoming effective. After an action is taken, the consent or consents relating thereto shall be filed with the minutes of the proceedings of the board of directors, or the committee or subcommittee thereof, in the same paper or electronic form as the minutes are maintained.

3.10 FEES AND COMPENSATION OF DIRECTORS

Unless otherwise restricted by the certificate of incorporation or these bylaws, the board of directors shall have the authority to fix the compensation of directors.

-16-

3.11 REMOVAL OF DIRECTORS

Consistent with Section 141(k) of the DGCL, so long as the board of directors remains classified as provided in Section 141(d) of the DGCL and unless otherwise provided in the certificate of incorporation, any director may be removed from office by the stockholders of the corporation only for cause.

No reduction of the authorized number of directors shall have the effect of removing any director prior to the expiration of such director’s term of office.

ARTICLE IV—COMMITTEES

4.1 COMMITTEES OF DIRECTORS

The board of directors may, by resolution passed by a majority of the Whole Board, designate one or more committees, each committee to consist of one or more of the directors of the corporation. The board of directors may designate one or more directors as alternate members of any committee, who may replace any absent or disqualified member at any meeting of the committee. In the absence or disqualification of a member of a committee, the member or members thereof present at any meeting and not disqualified from voting, whether or not such member or members constitute a quorum, may unanimously appoint another member of the board of directors to act at the meeting in the place of any such absent or disqualified member. Any such committee, to the extent provided in the resolution of the board of directors or in these bylaws, shall have and may exercise all the powers and authority of the board of directors in the management of the business and affairs of the corporation, and may authorize the seal of the corporation to be affixed to all papers that may require it; but no such committee shall have the power or authority to (i) approve or adopt, or recommend to the stockholders, any action or matter (other than the election or removal of directors) expressly required by the DGCL to be submitted to stockholders for approval, or (ii) adopt, amend or repeal any bylaw of the corporation.

4.2 COMMITTEE MINUTES

Each committee and subcommittee shall keep regular minutes of its meetings.

4.3 MEETINGS AND ACTION OF COMMITTEES

Unless otherwise specified by the board of directors, meetings and actions of committees and subcommittees shall be governed by, and held and taken in accordance with, the provisions of:

(i) Section 3.5 (place of meetings and meetings by telephone);

(ii) Section 3.6 (regular meetings);

(iii) Section 3.7 (special meetings and notice);

(iv) Section 3.8 (quorum; voting);

(v) Section 3.9 (action without a meeting); and

(vi) Section 7.4 (waiver of notice)

-17-

with such changes in the context of those bylaws as are necessary to substitute the committee or subcommittee and its members for the board of directors and its members. However:

(i) the time and place of regular meetings of committees or subcommittees may be determined either by resolution of the board of directors or by resolution of the committee or subcommittee;

(ii) special meetings of committees or subcommittees may also be called by resolution of the board of directors or the committee or subcommittee; and

(iii) notice of special meetings of committees and subcommittees shall also be given to all alternate members, as applicable, who shall have the right to attend all meetings of the committee or subcommittee. The board of directors or a committee or subcommittee may also adopt other rules for the government of any committee or subcommittee.

Any provision in the certificate of incorporation providing that one or more directors shall have more or less than one vote per director on any matter shall apply to voting in any committee or subcommittee, unless otherwise provided in the certificate of incorporation or these bylaws.

4.4 SUBCOMMITTEES

Unless otherwise provided in the certificate of incorporation, these bylaws or the resolutions of the board of directors designating the committee, a committee may create one or more subcommittees, each subcommittee to consist of one or more members of the committee, and delegate to a subcommittee any or all of the powers and authority of the committee.

ARTICLE V—OFFICERS

5.1 OFFICERS

The officers of the corporation shall be a president and a secretary. The corporation may also have, at the discretion of the board of directors, a chairperson of the board of directors, a vice chairperson of the board of directors, a chief executive officer, a chief financial officer or treasurer, one or more vice presidents, one or more assistant vice presidents, one or more assistant treasurers, one or more assistant secretaries and any such other officers as may be appointed in accordance with the provisions of these bylaws. Any number of offices may be held by the same person.

5.2 APPOINTMENT OF OFFICERS

The board of directors shall appoint the officers of the corporation, except such officers as may be appointed in accordance with the provisions of Section 5.3 of these bylaws, subject to the rights, if any, of an officer under any contract of employment.

5.3 SUBORDINATE OFFICERS

The board of directors may appoint, or empower any officer to appoint, such other officers as the business of the corporation may require. Each of such officers shall hold office for such period, have such authority, and perform such duties as are provided in these bylaws or as determined from time to time by the board of directors or, for the avoidance of doubt, by any duly authorized committee or subcommittee thereof or by any officer who has been conferred such power of determination.

-18-

5.4 REMOVAL AND RESIGNATION OF OFFICERS

Subject to the rights, if any, of an officer under any contract of employment, any officer may be removed, either with or without cause, by the board of directors or, for the avoidance of doubt, any duly authorized committee or subcommittee thereof or by any officer who has been conferred such power of removal.

Any officer may resign at any time by giving notice, in writing or by electronic transmission, to the corporation. Any resignation shall take effect at the date of the receipt of that notice or at any later time specified in that notice. Unless otherwise specified in the notice of resignation, the acceptance of the resignation shall not be necessary to make it effective. Any resignation is without prejudice to the rights, if any, of the corporation under any contract to which the officer is a party.

5.5 VACANCIES IN OFFICES

Any vacancy occurring in any office of the corporation shall be filled by the board of directors or as provided in Section 5.3.

5.6 REPRESENTATION OF SECURITIES OF OTHER ENTITIES

The chairperson of the board of directors, the chief executive officer, the president, any vice president, the treasurer, the secretary or assistant secretary of this corporation or any other person authorized by the board of directors or the chief executive officer, the president or a vice president, is authorized to vote, represent and exercise on behalf of this corporation all rights incident to any and all shares or other securities of, or interests in, or issued by, any other entity or entities, and all rights incident to any management authority conferred on the corporation in accordance with the governing documents of any entity or entities, standing in the name of this corporation, including the right to act by written consent. The authority granted herein may be exercised either by such person directly or by any other person authorized to do so by proxy or power of attorney duly executed by such person having the authority.

5.7 AUTHORITY AND DUTIES OF OFFICERS

All officers of the corporation shall respectively have such authority and perform such duties in the management of the business of the corporation as may be designated from time to time by the board of directors or, for the avoidance of doubt, any duly authorized committee or subcommittee thereof or by any officer who has been conferred such power of designation and, to the extent not so provided, as generally pertain to their respective offices, subject to the control of the board of directors.

ARTICLE VI—STOCK

6.1 STOCK CERTIFICATES; PARTLY PAID SHARES

The shares of the corporation shall be represented by certificates, provided that the board of directors may provide by resolution or resolutions that some or all of any or all classes or series of its stock shall be uncertificated shares. Any such resolution shall not apply to shares represented by a certificate until such

-19-

certificate is surrendered to the corporation. Unless otherwise provided by resolution of the board of directors, every holder of stock represented by certificates shall be entitled to have a certificate signed by, or in the name of, the corporation by any two officers of the corporation representing the number of shares registered in certificate form. Any or all of the signatures on the certificate may be a facsimile. In case any officer, transfer agent or registrar who has signed or whose facsimile signature has been placed upon a certificate has ceased to be such officer, transfer agent or registrar before such certificate is issued, it may be issued by the corporation with the same effect as if such person were such officer, transfer agent or registrar at the date of issue. The corporation shall not have power to issue a certificate in bearer form.

The corporation may issue the whole or any part of its shares as partly paid and subject to call for the remainder of the consideration to be paid therefor. Upon the face or back of each stock certificate issued to represent any such partly-paid shares, or upon the books and records of the corporation in the case of uncertificated partly-paid shares, the total amount of the consideration to be paid therefor and the amount paid thereon shall be stated. Upon the declaration of any dividend on fully-paid shares, the corporation shall declare a dividend upon partly-paid shares of the same class, but only upon the basis of the percentage of the consideration actually paid thereon.

6.2 SPECIAL DESIGNATION ON CERTIFICATES

If the corporation is authorized to issue more than one class of stock or more than one series of any class, then the powers, the designations, the preferences, and the relative, participating, optional or other special rights of each class of stock or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights shall be set forth in full or summarized on the face or back of the certificate that the corporation shall issue to represent such class or series of stock; provided, however, that, except as otherwise provided in Section 202 of the DGCL, in lieu of the foregoing requirements, there may be set forth on the face or back of the certificate that the corporation shall issue to represent such class or series of stock, a statement that the corporation will furnish without charge to each stockholder who so requests the powers, designations, preferences and relative, participating, optional or other special rights of each class of stock or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights. Within a reasonable time after the issuance or transfer of uncertificated stock, the registered owner thereof shall be given a notice, in writing or by electronic transmission, containing the information required to be set forth or stated on certificates pursuant to this Section 6.2 or Sections 151, 156, 202(a), 218(a) or 364 of the DGCL or with respect to this Section 6.2 a statement that the corporation will furnish without charge to each stockholder who so requests the powers, designations, preferences and relative, participating, optional or other special rights of each class of stock or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights. Except as otherwise expressly provided by law, the rights and obligations of the holders of uncertificated stock and the rights and obligations of the holders of certificates representing stock of the same class and series shall be identical.

6.3 LOST CERTIFICATES

Except as provided in this Section 6.3, no new certificates for shares shall be issued to replace a previously issued certificate unless the latter is surrendered to the corporation and cancelled at the same time. The corporation may issue a new certificate of stock or uncertificated shares in the place of any certificate theretofore issued by it, alleged to have been lost, stolen or destroyed, and the corporation may require the owner of the lost, stolen or destroyed certificate, or such owner’s legal representative, to give the corporation a bond sufficient to indemnify it against any claim that may be made against it on account of the alleged loss, theft or destruction of any such certificate or the issuance of such new certificate or uncertificated shares.

-20-

6.4 DIVIDENDS

The board of directors, subject to any restrictions contained in the certificate of incorporation or applicable law, may declare and pay dividends upon the shares of the corporation’s capital stock. Dividends may be paid in cash, in property, or in shares of the corporation’s capital stock, subject to the provisions of the certificate of incorporation.

The board of directors may set apart out of any of the funds of the corporation available for dividends a reserve or reserves for any proper purpose and may abolish any such reserve. Such purposes shall include but not be limited to equalizing dividends, repairing or maintaining any property of the corporation, and meeting contingencies.

6.5 TRANSFER OF STOCK

Transfers of record of shares of stock of the corporation shall be made only upon its books by the holders thereof, in person or by an attorney duly authorized, and, subject to Section 6.3 of these bylaws, if such stock is certificated, upon the surrender of a certificate or certificates for a like number of shares, properly endorsed or accompanied by proper evidence of succession, assignation or authority to transfer.

6.6 STOCK TRANSFER AGREEMENTS

The corporation shall have power to enter into and perform any agreement with any number of stockholders of any one or more classes or series of stock of the corporation to restrict the transfer of shares of stock of the corporation of any one or more classes or series owned by such stockholders in any manner not prohibited by the DGCL.

6.7 REGISTERED STOCKHOLDERS

The corporation:

(i) shall be entitled to recognize the exclusive right of a person registered on its books as the owner of shares to receive dividends and notices and to vote as such owner; and

(ii) shall not be bound to recognize any equitable or other claim to or interest in such share or shares on the part of another person, whether or not it shall have express or other notice thereof, except as otherwise provided by the laws of Delaware.

ARTICLE VII—MANNER OF GIVING NOTICE AND WAIVER

7.1 NOTICE OF STOCKHOLDERS’ MEETINGS

Notice of any meeting of stockholders shall be given in the manner set forth in the DGCL.

-21-

7.2 NOTICE TO STOCKHOLDERS SHARING AN ADDRESS

Except as otherwise prohibited under the DGCL, without limiting the manner by which notice otherwise may be given effectively to stockholders, any notice to stockholders given by the corporation under the provisions of the DGCL, the certificate of incorporation or these bylaws shall be effective if given by a single written notice to stockholders who share an address if consented to by the stockholders at that address to whom such notice is given. Any such consent shall be revocable by the stockholder by written notice to the corporation. Any stockholder who fails to object in writing to the corporation, within 60 days of having been given written notice by the corporation of its intention to send the single notice, shall be deemed to have consented to receiving such single written notice. This Section 7.2 shall not apply to Sections 164, 296, 311, 312 or 324 of the DGCL.

7.3 NOTICE TO PERSON WITH WHOM COMMUNICATION IS UNLAWFUL

Whenever notice is required to be given, under the DGCL, the certificate of incorporation or these bylaws, to any person with whom communication is unlawful, the giving of such notice to such person shall not be required and there shall be no duty to apply to any governmental authority or agency for a license or permit to give such notice to such person. Any action or meeting which shall be taken or held without notice to any such person with whom communication is unlawful shall have the same force and effect as if such notice had been duly given. In the event that the action taken by the corporation is such as to require the filing of a certificate under the DGCL, the certificate shall state, if such is the fact and if notice is required, that notice was given to all persons entitled to receive notice except such persons with whom communication is unlawful.

7.4 WAIVER OF NOTICE

Whenever notice is required to be given under any provision of the DGCL, the certificate of incorporation or these bylaws, a written waiver, signed by the person entitled to notice, or a waiver by electronic transmission by the person entitled to notice, whether before or after the time of the event for which notice is to be given, shall be deemed equivalent to notice. Attendance of a person at a meeting shall constitute a waiver of notice of such meeting, except when the person attends a meeting for the express purpose of objecting at the beginning of the meeting, to the transaction of any business because the meeting is not lawfully called or convened. Neither the business to be transacted at, nor the purpose of, any regular or special meeting need be specified in any written waiver of notice or any waiver by electronic transmission unless so required by the certificate of incorporation or these bylaws.

ARTICLE VIII—INDEMNIFICATION

8.1 INDEMNIFICATION OF DIRECTORS AND OFFICERS IN THIRD PARTY PROCEEDINGS

Subject to the other provisions of this Article VIII, the corporation shall indemnify, to the fullest extent permitted by the DGCL, as now or hereinafter in effect, any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (a “Proceeding”) (other than an action by or in the right of the corporation) by reason of the fact that such person is or was a director or officer of the corporation, or is or was a director or officer of the corporation serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by such person in connection with such Proceeding if such person acted in good faith and in a manner such person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe such person’s conduct was unlawful. The termination of any

-22-

Proceeding by judgment, order, settlement, conviction, or upon a plea of nolo contendere or its equivalent, shall not, of itself, create a presumption that the person did not act in good faith and in a manner which such person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had reasonable cause to believe that such person’s conduct was unlawful.

8.2 INDEMNIFICATION OF DIRECTORS AND OFFICERS IN ACTIONS BY OR IN THE RIGHT OF THE CORPORATION

Subject to the other provisions of this Article VIII, the corporation shall indemnify, to the fullest extent permitted by the DGCL, as now or hereinafter in effect, any person who was or is a party or is threatened to be made a party to any threatened, pending or completed Proceeding by or in the right of the corporation to procure a judgment in its favor by reason of the fact that such person is or was a director or officer of the corporation, or is or was a director or officer of the corporation serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorneys’ fees) actually and reasonably incurred by such person in connection with the defense or settlement of such Proceeding if such person acted in good faith and in a manner such person reasonably believed to be in or not opposed to the best interests of the corporation; except that no indemnification shall be made in respect of any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Court of Chancery or the court in which such Proceeding was brought shall determine upon application that, despite the adjudication of liability but in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the Court of Chancery or such other court shall deem proper.

8.3 SUCCESSFUL DEFENSE

To the extent that a present or former director or officer (for purposes of this Section 8.3 only, as such term is defined in Section 145(c)(1) of the DGCL) of the corporation has been successful on the merits or otherwise in defense of any Proceeding described in Section 8.1 or Section 8.2, or in defense of any claim, issue or matter therein, such person shall be indemnified against expenses (including attorneys’ fees) actually and reasonably incurred by such person in connection therewith. The corporation may indemnify any other person who is not a present or former director or officer of the corporation against expenses (including attorneys’ fees) actually and reasonably incurred by such person to the extent such person has been successful on the merits or otherwise in defense of any Proceeding described in Section 8.1 or Section 8.2, or in defense of any claim, issue or matter therein.

8.4 INDEMNIFICATION OF OTHERS

Subject to the other provisions of this Article VIII, the corporation shall have power to indemnify its employees and agents, or any other persons, to the extent not prohibited by the DGCL or other applicable law. The board of directors shall have the power to delegate to any person or persons identified in subsections (1) through (4) of Section 145(d) of the DGCL the determination of whether employees or agents shall be indemnified.

8.5 ADVANCED PAYMENT OF EXPENSES

Expenses (including attorneys’ fees) actually and reasonably incurred by an officer or director of the corporation in defending any Proceeding shall be paid by the corporation in advance of the final disposition of such Proceeding upon receipt of a written request therefor (together with documentation reasonably evidencing

-23-

such expenses) and an undertaking by or on behalf of the person to repay such amounts if it shall ultimately be determined that the person is not entitled to be indemnified under this Article VIII or the DGCL. Such expenses (including attorneys’ fees) actually and reasonably incurred by former directors and officers or other employees and agents of the corporation or by persons serving at the request of the corporation as directors, officers, employees or agents of another corporation, partnership, joint venture, trust or other enterprise may be so paid upon such terms and conditions, if any, as the corporation deems appropriate. The right to advancement of expenses shall not apply to any Proceeding (or any part of any Proceeding) for which indemnity is excluded pursuant to these bylaws, but shall apply to any Proceeding (or any part of any Proceeding) referenced in Section 8.6(ii) or 8.6(iii) prior to a determination that the person is not entitled to be indemnified by the corporation.

8.6 LIMITATION ON INDEMNIFICATION

Subject to the requirements in Section 8.3 and the DGCL, the corporation shall not be obligated to indemnify any person pursuant to this Article VIII in connection with any Proceeding (or any part of any Proceeding):

(i) for which payment has actually been made to or on behalf of such person under any statute, insurance policy, indemnity provision, vote or otherwise, except with respect to any excess beyond the amount paid;

(ii) for an accounting or disgorgement of profits pursuant to Section 16(b) of the 1934 Act, or similar provisions of federal, state or local statutory law or common law, if such person is held liable therefor (including pursuant to any settlement arrangements);

(iii) for any reimbursement of the corporation by such person of any bonus or other incentive-based or equity-based compensation or of any profits realized by such person from the sale of securities of the corporation, as required in each case under the 1934 Act (including any such reimbursements that arise from an accounting restatement of the corporation pursuant to Section 304 of the Sarbanes-Oxley Act of 2002 (the “Sarbanes-Oxley Act”), or the payment to the corporation of profits arising from the purchase and sale by such person of securities in violation of Section 306 of the Sarbanes-Oxley Act), if such person is held liable therefor (including pursuant to any settlement arrangements);

(iv) initiated by such person, including any Proceeding (or any part of any Proceeding) initiated by such person against the corporation or its directors, officers, employees, agents or other indemnitees, unless (a) the board of directors authorized the Proceeding (or the relevant part of the Proceeding) prior to its initiation, (b) the corporation provides the indemnification, in its sole discretion, pursuant to the powers vested in the corporation under applicable law, (c) otherwise required to be made under Section 8.7 or (d) otherwise required by applicable law; or

(v) if prohibited by applicable law.

8.7 DETERMINATION; CLAIM

If a claim for indemnification or advancement of expenses under this Article VIII is not paid in full within 90 days after receipt by the corporation of the written request therefor, the claimant shall be entitled to an adjudication by a court of competent jurisdiction of such claimant’s entitlement to such indemnification or advancement of expenses. The corporation shall indemnify such person against any and all expenses that are

-24-

actually and reasonably incurred by such person in connection with any action for indemnification or advancement of expenses from the corporation under this Article VIII, to the extent such person is successful in such action, and to the extent not prohibited by law. In any such suit, the corporation shall, to the fullest extent not prohibited by law, have the burden of proving that the claimant is not entitled to the requested indemnification or advancement of expenses.

8.8 NON-EXCLUSIVITY OF RIGHTS

The indemnification and advancement of expenses provided by, or granted pursuant to, this Article VIII shall not be deemed exclusive of any other rights to which those seeking indemnification or advancement of expenses may be entitled under the certificate of incorporation or any statute, bylaw, agreement, vote of stockholders or disinterested directors or otherwise, both as to action in such person’s official capacity and as to action in another capacity while holding such office. The corporation is specifically authorized to enter into individual contracts with any or all of its directors, officers, employees or agents respecting indemnification and advancement of expenses, to the fullest extent not prohibited by the DGCL or other applicable law.

8.9 INSURANCE

The corporation may purchase and maintain insurance on behalf of any person who is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise against any liability asserted against such person and incurred by such person in any such capacity, or arising out of such person’s status as such, whether or not the corporation would have the power to indemnify such person against such liability under the provisions of the DGCL.

8.10 SURVIVAL

The rights to indemnification and advancement of expenses conferred by this Article VIII shall continue as to a person who has ceased to be a director, officer, employee or agent and shall inure to the benefit of the heirs, executors and administrators of such a person.

8.11 EFFECT OF REPEAL OR MODIFICATION

A right to indemnification or to advancement of expenses arising under a provision of the certificate of incorporation or a bylaw shall not be eliminated or impaired by an amendment to or repeal or elimination of the certificate of incorporation or these bylaws after the occurrence of the act or omission that is the subject of the Proceeding for which indemnification or advancement of expenses is sought, unless the provision in effect at the time of such act or omission explicitly authorizes such elimination or impairment after such action or omission has occurred.

8.12 CERTAIN DEFINITIONS

For purposes of this Article VIII, references to the “corporation” shall include, in addition to the resulting entity, any constituent entity (including any constituent of a constituent) absorbed in a consolidation or merger which, if its separate existence had continued, would have had power and authority to indemnify its directors, officers, employees or agents, so that any person who is or was a director, officer, employee or agent of such constituent entity, or is or was serving at the request of such constituent entity as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, shall stand in the

-25-

same position under the provisions of this Article VIII with respect to the resulting or surviving entity as such person would have with respect to such constituent entity if its separate existence had continued. For purposes of this Article VIII, references to “other enterprises” shall include employee benefit plans; references to “fines” shall include any excise taxes assessed on a person with respect to an employee benefit plan; and references to “serving at the request of the corporation” shall include any service as a director, officer, employee or agent of the corporation which imposes duties on, or involves services by, such director, officer, employee or agent with respect to an employee benefit plan, its participants or beneficiaries; and a person who acted in good faith and in a manner such person reasonably believed to be in the interest of the participants and beneficiaries of an employee benefit plan shall be deemed to have acted in a manner “not opposed to the best interests of the corporation” as referred to in this Article VIII.

ARTICLE IX—GENERAL MATTERS

9.1 EXECUTION OF CORPORATE CONTRACTS AND INSTRUMENTS

Except as otherwise provided by law, the certificate of incorporation or these bylaws, the board of directors may authorize any officer or officers, or agent or agents, or employee or employees, to enter into any contract or execute any document or instrument in the name of and on behalf of the corporation; such authority may be general or confined to specific instances. Unless so authorized or ratified by the board of directors or within the agency power of an officer, agent or employee, no officer, agent or employee shall have any power or authority to bind the corporation by any contract or engagement or to pledge its credit or to render it liable for any purpose or for any amount.

9.2 FISCAL YEAR

The fiscal year of the corporation shall be fixed by resolution of the board of directors and may be changed by the board of directors.

9.3 SEAL

The corporation may adopt a corporate seal, which shall be adopted and which may be altered by the board of directors. The corporation may use the corporate seal by causing it or a facsimile thereof to be impressed or affixed or in any other manner reproduced.

9.4 CONSTRUCTION; DEFINITIONS

Unless the context requires otherwise, the general provisions, rules of construction, and definitions in the DGCL shall govern the construction of these bylaws. Without limiting the generality of this provision, the singular number includes the plural, the plural number includes the singular, and the term “person” includes a corporation, partnership, limited liability company, joint venture, trust or other enterprise, and a natural person. Any reference in these bylaws to a section of the DGCL shall be deemed to refer to such section as amended from time to time and any successor provisions thereto.

-26-

ARTICLE X—AMENDMENTS

These bylaws may be adopted, amended or repealed by the stockholders entitled to vote; provided, however, that the affirmative vote of the holders of at least 66 2/3% of the total voting power of outstanding voting securities, voting together as a single class, shall be required for the stockholders of the corporation to alter, amend or repeal, or adopt any bylaw inconsistent with, the following provisions of these bylaws: Article II, Sections 3.1, 3.2, 3.4 and 3.11 of Article III, Article VIII, and this Article X (including, without limitation, any such Article or Section as renumbered as a result of any amendment, alteration, change, repeal, or adoption of any other bylaw). The board of directors shall also have the power to adopt, amend or repeal bylaws; provided, however, that a bylaw amendment adopted by stockholders which specifies the votes that shall be necessary for the election of directors shall not be further amended or repealed by the board of directors.

ARTICLE XI—EXCLUSIVE FORUM

Unless the corporation consents in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware (or, if the Court of Chancery does not have jurisdiction, another State court in Delaware or the federal district court for the District of Delaware) shall, to the fullest extent permitted by law, be the sole and exclusive forum for (i) any derivative action or proceeding brought on behalf of the corporation, (ii) any action asserting a claim of breach of a fiduciary duty owed by any director, stockholder, officer or other employee of the corporation to the corporation or the corporation’s stockholders, (iii) any action arising pursuant to any provision of the DGCL or the certificate of incorporation or these bylaws (as either may be amended from time to time) or (iv) any action asserting a claim governed by the internal affairs doctrine, except for, as to each of (i) through (iv) above, any claim (A) as to which such court determines that there is an indispensable party not subject to the jurisdiction of such court (and the indispensable party does not consent to the personal jurisdiction of such court within 10 days following such determination), (B) which is vested in the exclusive jurisdiction of a court or forum other than such court, or (C) for which such court does not have subject matter jurisdiction.

Unless the corporation consents in writing to the selection of an alternative forum, the federal district courts of the United States of America shall be the sole and exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act of 1933, as amended, against any person in connection with any offering of the corporation’s securities, including, without limitation and for the avoidance of doubt, any auditor, underwriter, expert, control person or other defendant.

Any person or entity purchasing, holding or otherwise acquiring any interest in any security of the corporation shall be deemed to have notice of and consented to the provisions of this Article XI. This provision shall be enforceable by any party to a complaint covered by the provisions of this Article XI. For the avoidance of doubt, nothing contained in this Article XI shall apply to any claim brought to enforce a duty or liability created by the 1934 Act or any successor thereto.

-27-

ALECTOR, INC.

CERTIFICATE OF AMENDMENT OF BYLAWS

The undersigned hereby certifies that he or she is the duly elected, qualified, and acting Secretary or Assistant Secretary of Alector, Inc., a Delaware corporation and that the foregoing bylaws were amended and restated on June 15, 2023 by the corporation’s board of directors.

IN WITNESS WHEREOF, the undersigned has hereunto set his or her hand this 15th day of June, 2023.