Novartis AG — Director's Dealing 2016

Feb 18, 2016

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: PROTEOSTASIS THERAPEUTICS, INC. (PTI)
CIK: 0001445283
Period of Report: 2016-02-17

Reporting Person: Novartis Bioventures Ltd (10% Owner)
Reporting Person: NOVARTIS AG (10% Owner)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2016-02-17	Common Stock	C	1498791	—	Acquired	1498791	Direct
2016-02-17	Common Stock	P	375000	$8.00	Acquired	1873791	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2016-02-17	Series A Convertible Redeemable Preferred Stock	$	C	10000000	Disposed		Common Stock (1318932)	Direct
2016-02-17	Series B Convertible Redeemable Preferred Stock	$	C	1944315	Disposed		Common Stock (179859)	Direct

Footnotes

F1: This transaction represents the total number of shares of Common Stock of the Issuer (the "Issuer Common Stock") received upon the conversion of the Issuer's Series A Convertible Redeemable Preferred Stock (the "Series A Shares"), the payment of accrued dividends on the Series A Shares and the conversion of the Issuer's Series B Convertible Redeemable Preferred Stock (the "Series B Shares", collectively, the "Preferred Shares").

F2: These securities are held directly by Novartis Bioventures Ltd. ("Novartis Bioventures"). Novartis Bioventures is a corporation organized under the laws of Bermuda and is an indirect wholly-owned subsidiary of Novartis AG. Novartis AG is a corporation organized under the laws of Switzerland and is the publicly owned parent of Novartis Bioventures Ltd.

F3: These securities were purchased in connection with the initial public offering of the Issuer.

F4: The Preferred Shares automatically converted into Issuer Common Stock on a 10.8102-to-1 basis upon the closing of the initial public offering of the Issuer without payment or further consideration. The Preferred Shares were convertible at any time at the election of the Reporting Person and had no expiration date.

F5: These securities include shares of Issuer Common Stock received as payment for accrued dividends on the Series A Shares.