X0306 4 2015-05-12 1 0001339970 aTYR PHARMA INC LIFE 0001439589 Polaris Venture Management Co. V, L.L.C. C/O POLARIS VENTURE PARTNERS, 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02541 0 0 1 0 0001439590 Polaris Venture Partners V, L.P. 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02451 0 0 1 0 0001439587 Polaris Venture Partners Entrepreneurs' Fund V, L.P. 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02451 0 0 1 0 0001439588 Polaris Venture Partners Founders' Fund V, L.P. 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02451 0 0 1 0 0001439586 Polaris Venture Partners Special Founders' Fund V, L.P. 1000 WINTER STREET, SUITE 3350 WALTHAM MA 02451 0 0 1 0 Common Stock 2015-05-12 4 C 0 1674825 A 1674825 I By Polaris Venture Partners V, L.P. Common Stock 2015-05-12 4 C 0 32642 A 32642 I By Polaris Venture Partners Entrepreneurs' Fund V, L.P. Common Stock 2015-05-12 4 C 0 11472 A 11472 I By Polaris Venture Partners Founders' Fund V, L.P. Common Stock 2015-05-12 4 C 0 16748 A 16748 I Polaris Venture Partners Special Founders' Fund V, L.P. Common Stock 2015-05-12 4 C 0 89069 A 1763894 I By Polaris Venture Partners V, L.P. Common Stock 2015-05-12 4 C 0 1736 A 34378 I By Polaris Venture Partners Entrepreneurs' Fund V, L.P. Common Stock 2015-05-12 4 C 0 610 A 12082 I By Polaris Venture Partners Founders' Fund V, L.P. Common Stock 2015-05-12 4 C 0 890 A 17638 I Polaris Venture Partners Special Founders' Fund V, L.P. Series B Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 3473763 0.00 D Common Stock 436725 0 I By Polaris Venture Partners V, L.P. Series B Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 67704 0.00 D Common Stock 8512 0 I By Polaris Venture Partners Entrepreneurs' Fund V, L.P. Series B Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 23796 0.00 D Common Stock 2992 0 I By Polaris Venture Partners Founders' Fund V, L.P. Series B Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 34737 0.00 D Common Stock 4367 0 I Polaris Venture Partners Special Founders' Fund V, L.P. Series B-2 Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 4168683 0.00 D Common Stock 524090 0 I By Polaris Venture Partners V, L.P. Series B-2 Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 81248 0.00 D Common Stock 10214 0 I By Polaris Venture Partners Entrepreneurs' Fund V, L.P. Series B-2 Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 28556 0.00 D Common Stock 3590 0 I By Polaris Venture Partners Founders' Fund V, L.P. Series B-2 Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 41686 0.00 D Common Stock 5241 0 I By Polaris Venture Partners Special Founders' Fund V, L.P. Series C Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 4208756 0.00 D Common Stock 529128 0 I By Polaris Venture Partners V, L.P. Series C Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 82029 0.00 D Common Stock 10313 0 I By Polaris Venture Partners Entrepreneurs' Fund V, L.P. Series C Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 28831 0.00 D Common Stock 3624 0 I By Polaris Venture Partners Founders' Fund V, L.P. Series C Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 42087 0.00 D Common Stock 5291 0 I By Polaris Venture Partners Special Founders' Fund V, L.P. Series D Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 1470577 0.00 D Common Stock 184882 0 I By Polaris Venture Partners V, L.P. Series D Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 28661 0.00 D Common Stock 3603 0 I By Polaris Venture Partners Entrepreneurs' Fund V, L.P. Series D Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 10074 0.00 D Common Stock 1266 0 I By Polaris Venture Partners Founders' Fund V, L.P. Series D Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 14706 0.00 D Common Stock 1849 0 I By Polaris Venture Partners Special Founders' Fund V, L.P. Series E Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 862318 0.00 D Common Stock 89069 0 I By Polaris Venture Partners V, L.P. Series E Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 16806 0.00 D Common Stock 1736 0 I By Polaris Venture Partners Entrepreneurs' Fund V, L.P. Series E Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 5906 0.00 D Common Stock 610 0 I By Polaris Venture Partners Founders' Fund V, L.P. Series E Redeemable Convertible Preferred Stock 2015-05-12 4 C 0 8623 0.00 D Common Stock 890 0 I By Polaris Venture Partners Special Founders' Fund V, L.P. The aggregate number of shares of Issuer's Preferred Stock held by the Reporting Person converted into Common Stock immediately prior to the closing of the Issuer's initial public offering and has no expiration date. These shares converted into Common Stock on a 1-for-7.95413 basis. Reflects a 1-for-7.95413 stock conversion of the Issuer's Preferred Stock into Common Stock which became effective immediately prior to the closing of the Issuer's initial public offering. These shares are owned directly by Polaris Venture Partners V, L.P. ("Polaris V"), whose sole general partner is Polaris Venture Management Co. V, LLC ("Polaris Management"). Each of Jonathan A. Flint ("Flint") and Terrance G. McGuire ("McGuire") are the managing members of Polaris Management. Amir Nashat ("Nashat"), who is a member of the Issuer's Board of Directors, is a member of Polaris Management. Each of Flint, McGuire and Nashat, in their respective capacities with regard to Polaris Management, may be deemed to have shared voting and dispositive power over the shares held by each of Polaris V, Polaris Venture Partners Entrepreneurs' Fund V, L.P. ("Polaris Entrepreneurs' V"), Polaris Venture Partners Founders' Fund V, L.P. ("Polaris Founders' V") and Polaris Venture Partners Special Founders' Fund V, L.P. ("Polaris Special Founders' V", and together with Polaris V, Polaris Entrepreneurs' V and Polaris Founders' V, the "Polaris V Funds"). (Continued from Footnote 3) Each of Flint, McGuire, Nashat and Polaris Management disclaims beneficial ownership of these securities and this report shall not be deemed to be an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or any other purpose, except to the extent of their pecuniary interest therein. These shares are owned directly by Polaris Entrepreneurs' V, whose sole general partner is Polaris Management. Each of Flint and McGuire are the managing members of Polaris Management. Nashat, who is a member of the Issuer's Board of Directors, is a member of Polaris Management. Each of Flint, McGuire and Nashat, in their respective capacities with regard to Polaris Management, may be deemed to have shared voting and dispositive power over the shares held by each of the Polaris V Funds. Each of Flint, McGuire, Nashat and Polaris Management disclaims beneficial ownership of these securities and this report shall not be deemed to be an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or any other purpose, except to the extent of their pecuniary interest therein. These shares are owned directly by Polaris Founders' V, whose sole general partner is Polaris Management. Each of Flint and McGuire are the managing members of Polaris Management. Nashat, who is a member of the Issuer's Board of Directors, is a member of Polaris Management. Each of Flint, McGuire and Nashat, in their respective capacities with regard to Polaris Management, may be deemed to have shared voting and dispositive power over the shares held by each of the Polaris V Funds. Each of Flint, McGuire, Nashat and Polaris Management disclaims beneficial ownership of these securities and this report shall not be deemed to be an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or any other purpose, except to the extent of their pecuniary interest therein. These shares are owned directly by Polaris Special Founders' V, whose sole general partner is Polaris Management. Each of Flint and McGuire are the managing members of Polaris Management. Nashat, who is a member of the Issuer's Board of Directors, is a member of Polaris Management. Each of Flint, McGuire and Nashat, in their respective capacities with regard to Polaris Management, may be deemed to have shared voting and dispositive power over the shares held by each of the Polaris V Funds. Each of Flint, McGuire, Nashat and Polaris Management disclaims beneficial ownership of these securities and this report shall not be deemed to be an admission that any one of them is the beneficial owner of such securities for purposes of Section 16 or any other purpose, except to the extent of their pecuniary interest therein. The aggregate number of shares of Issuer's Preferred Stock held by the Reporting Person converted into Common Stock immediately prior to the closing of the Issuer's initial public offering and has no expiration date. These shares converted into Common Stock on a 1-for-9.6814 basis. Reflects a 1-for 9.6814 stock conversion of the Issuer's Preferred Stock into Common Stock which became effective immediately prior to the closing of the Issuer's initial public offering. /s/ John Gannon, Attorney-in-Fact for Polaris Venture Management Co. V, L.L.C. 2015-05-14 /s/ John Gannon, Attorney-in-Fact for Polaris Venture Management Co. V, L.L.C., the general partner of Polaris Venture Partners V, L.P. 2015-05-14 /s/ John Gannon, Attorney-in-Fact for Polaris Venture Management Co. V, L.L.C., the general partner of Polaris Venture Partners Entrepreneurs' Fund V, L.P. 2015-05-14 /s/ John Gannon, Attorney-in-Fact for Polaris Venture Management Co. V, L.L.C., the general partner of Polaris Venture Partners Founders' Fund V, L.P. 2015-05-14 /s/ John Gannon, Attorney-in-Fact for Polaris Venture Management Co. V, L.L.C., the general partner of Polaris Venture Partners Special Founders' Fund V, L.P. 2015-05-14