| ERP57 Protein | |
|---|---|
| Protein Name | ERP57 Protein |
| Gene Symbol | PDIA3 |
| UniProt ID | P27773 |
| PDB Structures | 3DNF, 3DNG, 4L39 |
| Molecular Weight | 57 kDa |
| Subcellular Localization | Endoplasmic Reticulum Lumen |
| Protein Family | Protein Disulfide Isomerase Family |
ERP57 is a protein involved in protein folding and ER homeostasis.[1] This protein plays important roles in the endoplasmic reticulum where it assists in protein folding and quality control.[2] In the context of neurodegenerative diseases, ERP57 is implicated in Alzheimer's disease, Parkinson's disease, and other disorders through various mechanisms.[3]
PDIA3 (ERP57) has a thioredoxin-like domain structure with four domains: a,b,b',a'. The a-type domains contain the active site motif CGHC (Cys-Gly-His-Cys) with redox-active cysteine residues. The b and b' domains are involved in substrate binding. PDIA3 forms complexes with calnexin (CALR) and calreticulin (CALR) in the ER. The protein has both oxidase and reductase activities and can catalyze disulfide bond formation, reduction, and isomerization.
PDIA3 is a multifunctional ER chaperone and enzyme that catalyzes disulfide bond formation in nascent proteins. It acts as an oxidase to form disulfide bonds and as an isomerase to rearrange incorrect disulfide bonds. PDIA3 is involved in the folding of glycosylated proteins and works together with the calnexin/calreticulin cycle. It also plays roles in ER-associated degradation (ERAD) and calcium homeostasis. PDIA3 can translocate to the cell surface where it has distinct functions.
PDIA3 is involved in neurodegenerative diseases through its chaperone functions. In Alzheimer's disease, PDIA3 interacts with APP and may influence amyloid-beta production. It is upregulated in AD brain as a response to ER stress. In Parkinson's disease, PDIA3 may help clear alpha-synuclein aggregates. Genetic variants have been associated with neurodegenerative disease risk. Altered PDIA3 function contributes to ER stress-mediated neuronal death.
Targeting PDIA3 is being explored for various therapeutic applications. In cancer, PDIA3 inhibitors are being developed. For neurodegeneration, enhancing PDIA3 function may help manage protein misfolding stress. However, systemic inhibition could have side effects due to its essential roles in protein folding. Gene therapy approaches to increase PDIA3 expression are being investigated.