X0206 3 2016-02-10 0 0001445283 PROTEOSTASIS THERAPEUTICS, INC. PTI 0001663552 Kelly Jeffrey W. 200 TECHNOLOGY SQUARE, 4TH FLOOR CAMBRIDGE MA 02139 1 0 0 0 Common Stock 98411 D Stock Option (Right to Buy) 2.49 2021-09-22 Common Stock 13875 D These securities are fully vested. Exhibit List - Exhibit 24.1 - Power of Attorney /s/ Janet L. Smart, Attorney-in-Fact 2016-02-10