Calumenin (CALU) (CALU)

Calumenin (CALU), also known as Crocalbin, is a 45-kDa calcium-binding protein that resides in the endoplasmic reticulum (ER) and the Golgi apparatus (UniProt O43852). As a member of the CREC family, it contains multiple EF-hand motifs and functions as a molecular chaperone, assisting in the folding and sorting of proteins within the secretory pathway (GeneCards). One of its most significant regulatory roles is the inhibition of gamma-glutamyl carboxylase (GGCX), an enzyme essential for the activation of vitamin K-dependent proteins involved in blood coagulation and bone metabolism (PMID: 9218460). In clinical contexts, calumenin is often overexpressed in malignant tumors, such as lung and colon cancer, where it facilitates epithelial-mesenchymal transition (EMT), cell migration, and metastasis (NCBI Gene 813). It is also associated with cardiovascular diseases, including arterial calcification and atherosclerosis, and has been linked to warfarin resistance in patients (PMID: 10631319). Although primarily studied as a biomarker for cancer progression, calumenin represents a potential therapeutic target for inhibiting metastasis and managing thrombotic disorders (PMC6412345).

Other names

CrocalbinCalcium-binding protein 45CBP-45IEF SSP 9302Crocalbin-like protein

Inhibition of gamma-glutamyl carboxylase (GGCX); modulation of SERCA and ryanodine receptor activity; chaperone-like activity in the endoplasmic reticulum