BiP prevents rod opsin aggregation.

ABSTRACT: Mutations in rod opsin-the light-sensitive protein of rod cells-cause retinitis pigmentosa. Many rod opsin mutations lead to protein misfolding, and therefore it is important to understand the role of molecular chaperones in rod opsin biogenesis. We show that BiP (HSPA5) prevents the aggregation of rod opsin. Cleavage of BiP with the subtilase cytotoxin SubAB results in endoplasmic reticulum (ER) retention and ubiquitylation of wild-type (WT) rod opsin (WT-green fluorescent protein [GFP]) at the ER. Fluorescence recovery after photobleaching reveals that WT-GFP is usually mobile in the ER. By contrast, depletion of BiP activity by treatment with SubAB or coexpression of a BiP ATPase mutant, BiP(T37G), decreases WT-GFP mobility to below that of the misfolding P23H mutant of rod opsin (P23H-

SUBMITTER: Athanasiou D 

PROVIDER: S-EPMC3442401 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature