SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13G

Under the Securities Exchange Act of 1934

(Amendment No. 1)*

ATyr Pharma, Inc.

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

002120103

(CUSIP Number)

December 31, 2017

(Date of Event which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes)

Item 1.

Item 2.

Item 3. Not applicable.

Item 4. Ownership.

The following beneficial ownership information is provided as of December 31, 2015.

Please see Attachment A

Item 5. Ownership of Five Percent or Less of a Class

If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than 5 percent of the class of securities, check the following ¨

Item 6. Ownership of More than Five Percent on Behalf of Another Person

Not applicable.

Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company.

Not applicable.

Item 8. Identification and Classification of Members of the Group

No reporting person is a member of a group as defined in Section 240.13d-1(b)(1)(ii)(J) of the Act.

Item 9. Notice of Dissolution of Group

Not applicable.

Item 10. Certification

Not applicable.

EXHIBITS

A: Joint Filing Statement

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: February 6, 2018

EXHIBIT A

AGREEMENT OF JOINT FILING

We, the undersigned, hereby express our agreement that the attached Schedule 13G is filed on behalf of us.

Date: February 6, 2018

Attachment A

Alta Partners VIII, L.P. beneficially owns 1,777,875 shares of Common Stock and exercises sole voting and dispositive control over such shares, except to the extent set forth below.

Alta Partners Management VIII, LLC is the general partner of Alta Partners VIII, L.P. and may be deemed to share the right to direct the voting and dispositive control over the shares held by such fund. Alta Partners Management VIII, LLC disclaims beneficial ownership of all such shares, except to the extent of its pecuniary interest therein.

Mr. Daniel Janney is a managing director of Alta Partners Management VIII, LLC and may be deemed to share the right to direct the voting and dispositive control over the shares held by such fund. Mr. Janney disclaims beneficial ownership of all such shares, except to the extent of his pecuniary interest therein.

Mr. Guy Nohra is a managing director of Alta Partners Management VIII, LLC and may be deemed to share the right to direct the voting and dispositive control over the shares held by such fund. Mr. Nohra disclaims beneficial ownership of all such shares, except to the extent of his pecuniary interest therein.

Ms. Farah Champsi is a managing director of Alta Partners Management VIII, LLC and may be deemed to share the right to direct the voting and dispositive control over the shares held by such fund. Ms. Champsi disclaims beneficial ownership of all such shares, except to the extent of her pecuniary interest therein.