Protein disulfide-isomerase A1 (PDIA1) (PDIA1)

Protein disulfide-isomerase A1 (PDIA1), encoded by the P4HB gene, is a 57 kDa enzyme primarily localized to the endoplasmic reticulum (ER) lumen where it catalyzes the formation, breakage, and rearrangement of disulfide bonds (UniProt P07237). As a member of the thioredoxin superfamily, it contains two catalytic thioredoxin-like domains that are essential for its oxidoreductase activity and proper protein folding (PubMed: 28259441). PDIA1 also functions as a molecular chaperone, preventing the aggregation of misfolded proteins independent of its enzymatic activity (PubMed: 10652314). In many cancers, PDIA1 is significantly upregulated to accommodate the increased demand for protein synthesis and to protect against ER stress-induced apoptosis, making it a target for small-molecule inhibitors like PACMA-31 (PubMed: 24658274). Additionally, PDIA1 is secreted by endothelial cells and platelets during vascular injury, where it facilitates thrombus formation, positioning it as a potential target for antithrombotic therapy (PubMed: 22544246). The enzyme's involvement in neurodegenerative diseases stems from its role in managing protein misfolding, where its dysfunction can lead to the accumulation of toxic protein aggregates (PubMed: 21832057). Therapeutic strategies targeting PDIA1 often focus on inhibiting its redox-active sites to disrupt these pathological processes. However, the ubiquity of PDIA1 in the ER of all cell types presents a challenge for achieving tissue-specific inhibition without systemic toxicity.

Other names

P4HBProlyl 4-hydroxylase subunit betaPDIERBA2LPO4DBDSIGITPHDB

Inhibition of the thioredoxin-like catalytic domains (a and a') to prevent the formation and rearrangement of disulfide bonds in substrate proteins, leading to endoplasmic reticulum stress and apoptosis in malignant cells or inhibition of platelet-mediated thrombus formation (PubMed: 24658274, PubMed: 22544246).