DNAJB9

This gene is a member of the J protein family. J proteins function in many cellular processes by regulating the ATPase activity of 70 kDa heat shock proteins. This gene is a member of the type 2 subgroup of DnaJ proteins. The encoded protein is localized to the endoplasmic reticulum. This protein is induced by endoplasmic reticulum stress and plays a role in protecting stressed cells from apoptosis.

Full Name

DnaJ (Hsp40) homolog, subfamily B, member 9

Function

Co-chaperone for Hsp70 protein HSPA5/BiP that acts as a key repressor of the ERN1/IRE1-mediated unfolded protein response (UPR) (By similarity).

J domain-containing co-chaperones stimulate the ATPase activity of Hsp70 proteins and are required for efficient substrate recognition by Hsp70 proteins (PubMed:18400946).

In the unstressed endoplasmic reticulum, interacts with the luminal region of ERN1/IRE1 and selectively recruits HSPA5/BiP: HSPA5/BiP disrupts the dimerization of the active ERN1/IRE1 luminal region, thereby inactivating ERN1/IRE1 (By similarity).

Also involved in endoplasmic reticulum-associated degradation (ERAD) of misfolded proteins. Required for survival of B-cell progenitors and normal antibody production (By similarity).

Biological Process

B cell differentiation Source: UniProtKB
Negative regulation of IRE1-mediated unfolded protein response Source: UniProtKB
Positive regulation of immunoglobulin production Source: UniProtKB
Response to endoplasmic reticulum stress Source: UniProtKB
Response to unfolded protein Source: UniProtKB-KW
Ubiquitin-dependent ERAD pathway Source: UniProtKB

Cellular Location

Endoplasmic reticulum lumen