DNAJB9
Description
The DNAJB9 (DnaJ heat shock protein family (Hsp40) member B9) is a protein-coding gene located on chromosome 7.
DNAJB9 is a protein that in humans is encoded by the DNAJB9 gene.
DNAJB9 acts as a co-chaperone for the Hsp70 protein HSPA5/BiP, playing a key role in repressing the unfolded protein response (UPR) mediated by ERN1/IRE1. DNAJB9 enhances the ATPase activity of Hsp70 proteins, facilitating efficient substrate recognition. In the unstressed endoplasmic reticulum (ER), DNAJB9 interacts with the luminal region of ERN1/IRE1, recruiting HSPA5/BiP. This interaction disrupts the dimerization of active ERN1/IRE1, effectively inactivating it. DNAJB9 is also involved in the ER-associated degradation (ERAD) of misfolded proteins. Its presence is essential for the survival of B-cell progenitors and normal antibody production.
DNAJB9 is also known as ERdj4, MDG-1, MDG1, MST049, MSTP049.
Associated Diseases
- cystic fibrosis
- exercise-induced hyperinsulinism
- hyperinsulinemic hypoglycemia, familial, 2
- hypoinsulinemic hypoglycemia and body hemihypertrophy
- hyperinsulinism due to HNF1A deficiency
- autosomal dominant hyperinsulinism due to Kir6.2 deficiency
- autosomal dominant hyperinsulinism due to SUR1 deficiency
- GCGR-related hyperglucagonemia
- osteogenesis imperfecta
