Exhibit 24.1

                            LIMITED POWER OF ATTORNEY

        The undersigned hereby constitutes and appoints each of Meenu Chhabra
and John M. Mutkoski, signing singly, and with full power of
substitution, the undersigned's true and lawful attorney-in-fact to:

        (1) Complete and execute for and on behalf of the undersigned, in the
undersigned's capacity as an officer, director and/or ten percent (10%)
shareholder of Proteostasis Therapeutics, Inc. (the "Company") any and all
instruments, certificates and documents required to be executed on behalf of the
undersigned as an individual or on behalf of the undersigned's company or
partnership, as the case may be, pursuant to Section 13 and Section 16 of the
Securities Exchange Act of 1934, as amended (the "Exchange Act") or the rules
and regulations thereunder;

        (2) do and perform any and all acts for and on behalf of the undersigned
which may be necessary or desirable to complete and execute any such
instruments, certificates or documents required to be filed pursuant to Section
13 and Section 16 of the Exchange Act or the rules or regulations thereunder,
and timely file such form(s) with the SEC and any securities exchange and any
stock exchange or similar authority; and

        (3) take any other action of any type whatsoever in connection with the
foregoing which, in the opinion of such attorney-in-fact, may be of benefit to,
in the best interest of, or legally required by, the undersigned, it being
understood that the documents executed by any such attorney-in-fact on behalf of
the undersigned pursuant to this Power of Attorney shall be in such form and
shall contain such terms and conditions as such attorney-in-fact may approve in
such attorney-in-fact's discretion.

        The undersigned hereby grants to each such attorney-in-fact, acting
singly, full power and authority to do and perform any and every act which is
necessary, proper or desirable to be done in the exercise of any of the rights
and powers herein granted, as fully to all intents and purposes as the
undersigned might or could do if personally present, with full power of
substitution or revocation, hereby ratifying and confirming all that any such
attorney-in-fact, or any such attorney-in-fact's substitute or substitutes,
shall lawfully do or cause to be done by virtue of this power of attorney and
the rights and powers herein granted. The undersigned acknowledges that each of
the foregoing attorneys-in-fact, in serving in such capacity at the request of
the undersigned, are not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 13 or Section 16 of the
Exchange Act. The undersigned hereby agrees to indemnify the attorneys-in-fact
and the Company from and against any demand, damage, loss, cost or expense
arising from any false or misleading information provided by the undersigned to
the attorneys-in-fact.

        This Power of Attorney shall remain in full force and effect until the
undersigned is no longer required to file any instruments, certificates and
documents pursuant to Section 13 and Section 16 of the Exchange Act or the rules
or regulations thereunder with respect to the undersigned's holdings of and
transactions in securities issued by the Company, unless earlier revoked by the
undersigned in a signed writing delivered to the foregoing attorneys-in-fact.
This Power of Attorney supersedes any prior power of attorney in connection with
the undersigned's capacity as an officer and/or director of the Company. This
Power of Attorney shall expire as to any individual attorney-in-fact if such
attorney-in-fact ceases to be an executive officer of, or legal counsel to, the
Company.

        IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of February 9, 2016.

                                        /s/ Janet Smart, Ph.D.,J.D.
                                        ------------------------------
                                        Janet Smart, Ph.D.,J.D.