SGTA recognizes a noncanonical ubiquitin-like domain in the Bag6-Ubl4A-Trc35 complex to promote endoplasmic reticulum-associated degradation.

ABSTRACT: Elimination of aberrantly folded polypeptides from the endoplasmic reticulum (ER) by the ER-associated degradation (ERAD) system promotes cell survival under stress conditions. This quality control mechanism requires movement of misfolded proteins across the ER membrane for targeting to the cytosolic proteasome, a process facilitated by a "holdase" complex, consisting of Bag6 and the cofactors Ubl4A and Trc35. This multiprotein complex also participates in several other protein quality control processes. Here, we report SGTA as a component of the Bag6 system, which cooperates with Bag6 to channel dislocated ERAD substrates that are prone to aggregation. Using nuclear magnetic resonance spectroscopy and biochemical assays, we demonstrate that SGTA contains a noncanonical ubiquitin-like-bind

SUBMITTER: Xu Y 

PROVIDER: S-EPMC3534891 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature