CALR

Calreticulin (CALR) is the soluble endoplasmic reticulum-luminal lectin chaperone that, together with the membrane-bound paralog calnexin, constitutes the central calnexin/calreticulin cycle of ER glycoprotein quality control. Its globular lectin domain binds monoglucosylated N-glycans (Glc1Man9GlcNAc2) on nearly all nascent glycoproteins, while its extended proline-rich P domain recruits the oxidoreductase ERp57 (PDIA3) and the peptidyl-prolyl isomerase cyclophilin B to promote folding, oligomeric assembly, and retention of incorrectly folded glycoproteins, triaging terminally misfolded clients toward degradation. Calreticulin is a major high-capacity, low-affinity calcium-binding protein that regulates ER calcium storage and homeostasis. It is a key chaperone in the major histocompatibility complex (MHC) class I peptide loading complex, where it stabilizes peptide-receptive MHC I and couples optimal epitope selection to glycan processing. Beyond the ER, calreticulin has well-documented secondary roles: a cell-surface and extracellular "eat-me" signal that promotes phagocytic clearance of apoptotic and stressed cells (immunogenic cell death), C1q/complement interactions, and additional context-specific cytosolic and nuclear activities.

Disorders

Relationship is the entry's genetic[].relationship_type. untyped means the entry has a genetic record for the gene but does not type it; its free-text association is shown instead.