a protein disulfide isomerase found in the endoplasmic reticulum lumen. Catalyzes the rearrangement of both intrachain and interchain disulfide bonds in proteins to form the native structures. An essential component of the peptide-loading complex of the major histocompatibility complex class I pathway. Note: This description may include information from UniProtKB.
Molecular Function: cysteine-type endopeptidase activity; disulfide oxidoreductase activity; peptide disulfide oxidoreductase activity; phospholipase C activity; protein binding; protein disulfide isomerase activity; RNA binding
Biological Process: antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-dependent; antigen processing and presentation of peptide antigen via MHC class I; protein folding; protein import into nucleus; protein retention in ER; signal transduction