ERdj5, an Endoplasmic Reticulum (ER)-resident Protein Containing DnaJ and Thioredoxin Domains, Is Expressed in Secretory Cells or following ER Stress

TLDR

The ER contains numerous chaperones and enzymes that facilitate folding, assembly, and disulfide bond formation of nascent secretory proteins. The study aims to characterize a novel human ER co‑chaperone, ERdj5, which contains DnaJ, protein‑disulfide isomerase, and thioredoxin domains. ERdj5, a ubiquitously expressed ER protein abundant in secretory cells, interacts with BiP via its DnaJ domain in an ATP‑dependent manner, is conserved in *C.

Abstract

A complex array of chaperones and enzymes reside in the endoplasmic reticulum (ER) to assist the folding and assembly of and the disulfide bond formation in nascent secretory proteins. Here we characterize a novel human putative ER co-chaperone (ERdj5) containing domains resembling DnaJ, protein-disulfide isomerase, and thioredoxin domains. Homologs of ERdj5 have been found in <i>Caenorhabditis elegans</i> and <i>Mus musculus.</i> In <i>vitro</i>experiments demonstrated that ERdj5 interacts via its DnaJ domain with BiP in an ATP-dependent manner. ERdj5 is a ubiquitous protein localized in the ER and is particularly abundant in secretory cells. Its transcription is induced during ER stress, suggesting potential roles for ERdj5 in protein folding and translocation across the ER membrane.