SCHEDULE 13G
Amendment No. 0
PROTEOSTASIS THERAPEUTICS INC
COMMON STOCK
Cusip #74373B109
Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:
[ ] Rule 13d-1(b)
[x] Rule 13d-1(c)
[ ] Rule 13d-1(d)
Cusip #74373B109
Item 1: Reporting Person - FMR LLC
Item 2: (a) [ ]
(b) [ ]
Item 4: Delaware
Item 5: 1,877,812
Item 6: 0
Item 7: 1,877,812
Item 8: 0
Item 9: 1,877,812
Item 11: 9.825%
Item 12: HC
Cusip #74373B109
Item 1: Reporting Person - Abigail P. Johnson
Item 2: (a) [ ]
(b) [ ]
Item 4: United States of America
Item 5: 0
Item 6: 0
Item 7: 1,877,812
Item 8: 0
Item 9: 1,877,812
Item 11: 9.825%
Item 12: IN
Item 1(a). Name of Issuer:
PROTEOSTASIS THERAPEUTICS INC
Item 1(b). Address of Issuer's Principal Executive Offices:
200 Technology Square, 4th Floor
Cambridge, MA 02139
USA
Item 2(a). Name of Person Filing:
FMR LLC
Item 2(b). Address or Principal Business Office or, if None,
Residence:
245 Summer Street, Boston, Massachusetts 02210
Item 2(c). Citizenship:
Not applicable
Item 2(d). Title of Class of Securities:
COMMON STOCK
Item 2(e). CUSIP Number:
74373B109
Item 3. Not Applicable
Item 4. Ownership
(a) Amount Beneficially Owned: 1,877,812
(b) Percent of Class: 9.825%
(c) Number of shares as to which such person has:
(i) sole power to vote or to direct the vote:
1,877,812
(ii) shared power to vote or to direct the vote: 0
(iii) sole power to dispose or to direct the
disposition of: 1,877,812
(iv) shared power to dispose or to direct the
disposition of: 0
Item 5. Ownership of Five Percent or Less of a Class.
Not applicable.
Item 6. Ownership of More than Five Percent on Behalf of Another
Person.
The interest of one person, F-Prime Capital Partners Healthcare Fund II LP,
in the COMMON STOCK of PROTEOSTASIS THERAPEUTICS INC, amounted to 1,877,812
shares or 9.825% of the total outstanding COMMON STOCK at February 17, 2016.
Item 7. Identification and Classification of the Subsidiary Which
Acquired the Security Being Reported on By the Parent Holding Company.
See attached Exhibit A.
Item 8. Identification and Classification of Members of the Group.
Not applicable.
Item 9. Notice of Dissolution of Group.
Not applicable.
Item 10. Certifications.
By signing below I certify that, to the best of my knowledge and belief,
the securities referred to above were not acquired and are not held for the
purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in
connection with or as a participant in any transaction having that purpose
or effect.
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.
February 18, 2016
Date
/s/ Daniel T. Gallagher
Signature
Daniel T. Gallagher
Duly authorized under Power of Attorney effective as of November 30,
2015, by and on behalf of FMR LLC and its direct and indirect subsidiaries*
* This power of attorney is incorporated herein by reference to Exhibit 24
to the Form 4 filed by FMR LLC on February 18, 2016, accession number:
0000315066-16-005625
Exhibit A
Pursuant to the instructions in Item 7 of Schedule 13G,
the following table lists the identity and Item 3 classification, if
applicable, of each relevant entity that beneficially owns shares of the
security class being reported on this Schedule 13G.
Entity ITEM 3 Classification
IMPRESA MANAGEMENT LLC * IA
* Entity beneficially owns 5% or greater of the outstanding shares of the
security class being reported on this Schedule 13G.
Abigail P. Johnson is a Director, the Vice Chairman, the
Chief Executive Officer and the President of FMR LLC.
Members of the Johnson family, including Abigail P.
Johnson, are the predominant owners, directly or through trusts, of Series
B voting common shares of FMR LLC, representing 49% of the voting power of
FMR LLC. The Johnson family group and all other Series B shareholders have
entered into a shareholders' voting agreement under which all Series B
voting common shares will be voted in accordance with the majority vote of
Series B voting common shares. Accordingly, through their ownership of
voting common shares and the execution of the shareholders' voting
agreement, members of the Johnson family may be deemed, under the
Investment Company Act of 1940, to form a controlling group with respect to
FMR LLC.
This filing reflects the securities beneficially owned, or
that may be deemed to be beneficially owned, by FMR LLC, certain of its
subsidiaries and affiliates, and other companies (collectively, the "FMR
Reporters"). This filing does not reflect securities, if any, beneficially
owned by certain other companies whose beneficial ownership of securities
is disaggregated from that of the FMR Reporters in accordance with
Securities and Exchange Commission Release No. 34-39538 (January 12, 1998).
RULE 13d-1(k)(1) AGREEMENT
The undersigned persons, on February 18, 2016, agree and
consent to the joint filing on their behalf of this Schedule 13G in
connection with their beneficial ownership of the COMMON STOCK of
PROTEOSTASIS THERAPEUTICS INC at February 17, 2016.
FMR LLC
By /s/ Daniel T. Gallagher
Daniel T. Gallagher
Duly authorized under Power of Attorney effective as of November 30,
2015, by and on behalf of FMR LLC and its direct and indirect subsidiaries*
Abigail P. Johnson
By /s/ Daniel T. Gallagher
Daniel T. Gallagher
Duly authorized under Power of Attorney effective as of June 18,
2014, by and on behalf of Abigail P. Johnson*
* This power of attorney is incorporated herein by reference to Exhibit 24
to the Form 4 filed by FMR LLC on February 18, 2016, accession number:
0000315066-16-005625