Encoded by the CALU gene, calumenin is a protein found within the human body, and specifically within the endoplasmic reticulum (ER). Calumenin is a calcium-binding protein and contributes to protein sorting and folding. It has been categorized as being in the EF-hand superfamily within the Golgi apparatus – the CERC. The CERC consists of Cab-45, Erc-55, reticulocalbin, and calumenin.
Little of substance is known about calumenin, a recently discovered protein. However, it has been noted that calumenin does appear to reduce the potential for cardiac injury by inhibiting apoptosis initiated by the endoplasmic reticulum during viral myocarditis. It also has a role in alleviating ER stress, which can lead to cell death. As well as this, CALU has been shown to have an influence on cell mobility, invasion, migration, and even metastasis. This latter, however, has only been noted during specific events including coagulation, wound healing, immune response, and tumorigenesis. Studies are ongoing regarding the link between cancer cells and calumenin, and what has been noted so far is that the higher the level of calumenin in lesions, the more aggressive the cancer, and the shorter the survival span for the patients involved. At the very least, this may lead to better detection rates for some cancers, which could improve survival rates overall, depending on the variables involved.