Abstract
Endoplasmic reticulum (ER)-associated degradation (ERAD) represents a principle quality control mechanism to clear misfolded proteins in the ER; however, its physiological significance and the nature of endogenous ERAD substrates remain largely unexplored. Here we discover that IRE1α, the sensor of the unfolded protein response (UPR), is a bona fide substrate of the Sel1L-Hrd1 ERAD complex. ERAD-mediated IRE1α degradation occurs under basal conditions in a BiP-dependent manner, requires both the intramembrane hydrophilic residues of IRE1α and the lectin protein OS9, and is attenuated by ER stress. ERAD deficiency causes IRE1α protein stabilization, accumulation and mild activation both in vitro and in vivo. Although enterocyte-specific Sel1L-knockout mice (Sel1L IEC) are viable and seem normal, they are highly susceptible to experimental colitis and inflammation-associated dysbiosis, in an IRE1α-dependent but CHOP-independent manner. Hence, Sel1L-Hrd1 ERAD serves a distinct, essential function in restraint of IRE1α signalling in vivo by managing its protein turnover.
Original language | English (US) |
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Pages (from-to) | 1546-1555 |
Number of pages | 10 |
Journal | Nature Cell Biology |
Volume | 17 |
Issue number | 12 |
DOIs | |
State | Published - Nov 27 2015 |
Funding
We thank K.-L. Tung for help with the organoid culture; and other members of the Qi laboratory for comments and technical assistance. S.S. is an International Student Research Fellow of the Howard Hughes Medical Institute (59107338). L.Q. is the recipient of the Junior Faculty and Career Development Awards from American Diabetes Association (ADA). This work was supported by R21AI085332 (G.E.D.), 1R03AI114344 (H.W.), Chinese National Natural Science Foundation Grant 31371391 (Q.L.), National Heart, Lung, and Blood Institute Proteomics Center Award HHSN268201000035C, R01 MH067880 and 8P41GM103533-17 (J.R.Y. III), NIH R01DK105393, R01GM113188, UL1TR000457 of the Clinical and Translation Science Center at Weill Cornell Medical College, ADA 1-12-CD-04 and Cornell VERG seed grant (L.Q.).
ASJC Scopus subject areas
- Cell Biology