Binds 2 calcium ions per subunit. Widely expressed at low levels with highest levels in small intestine, testis and brain. Very low expression in endothelial cells, monocytes, neutrophils and lymphocytes. Isoform 1 is not expressed in small intestine. Not induced by bacterial lipopolysaccharideS (LPS) or IL1/interleukin-1 in endothelium, monocytes or neutrophils. Not induced by PHA in lymphocytes. Not expressed in small intestine.