The pH-dependent Client Release from the Collagen-specific Chaperone HSP47 Is Triggered by a Tandem Histidine Pair.

ABSTRACT: Heat shock protein 47 (HSP47) is an endoplasmic reticulum (ER)-resident collagen-specific chaperone and essential for proper formation of the characteristic collagen triple helix. It preferentially binds to the folded conformation of its clients and accompanies them from the ER to the Golgi compartment, where it releases them and is recycled back to the ER. Unlike other chaperones, the binding and release cycles are not governed by nucleotide exchange and hydrolysis, but presumably the dissociation of the HSP47-procollagen complex is triggered by the lower pH in the Golgi (pH 6.3) compared with the ER (pH 7.4). Histidine residues have been suggested as triggers due to their approximate textbook pKa value of 6.1 for their side chains. We present here an extensive theoretical and experimenta

SUBMITTER: Oecal S 

PROVIDER: S-EPMC4933464 | biostudies-literature | 2016 Jun

REPOSITORIES: biostudies-literature