PDIA3
Function
Protein disulfide isomerase that catalyzes the formation, isomerization, and reduction or oxidation of disulfide bonds in client proteins and functions as a protein folding chaperone (PubMed:11825568, PubMed:16193070, PubMed:27897272, PubMed:36104323, PubMed:7487104). Core component of the major histocompatibility complex class I (MHC I) peptide loading complex where it functions as an essential folding chaperone for TAPBP. Through TAPBP, assists the dynamic assembly of the MHC I complex with high affinity antigens in the endoplasmic reticulum. Therefore, plays a crucial role in the presentation of antigens to cytotoxic T cells in adaptive immunity (PubMed:35948544, PubMed:36104323).
Post-translational modifications
Within the major histocompatibility complex class I (MHC I) peptide loading complex forms reversible disulfide-linked heterodimers with TAPBP as part of its protein folding chaperone activity. This is essential to assist the dynamic assembly of the MHC I complex with high affinity antigens in the endoplasmic reticulum.
Phosphorylated.
Sequence Similarities
Belongs to the protein disulfide isomerase family.
Tissue Specificity
Detected in the flagellum and head region of spermatozoa (at protein level) (PubMed:20400973). Expressed in liver, stomach and colon (at protein level). Expressed in gastric parietal cells and chief cells (at protein level) (PubMed:24188822).
Cellular localization
- Endoplasmic reticulum
- Endoplasmic reticulum lumen
- Melanosome
- Identified by mass spectrometry in melanosome fractions from stage I to stage IV (PubMed:12643545).
Alternative names
ERP57, ERP60, GRP58, PDIA3, Protein disulfide-isomerase A3, 58 kDa glucose-regulated protein, 58 kDa microsomal protein, Disulfide isomerase ER-60, Endoplasmic reticulum resident protein 57, Endoplasmic reticulum resident protein 60, p58, ER protein 57, ERp57, ER protein 60, ERp60