Gene:
S100 calcium binding protein G
Gene ID:
203602
Symbol:
S100G
Species:
1000
Description:
Calbindin D9K, the vitamin D-dependent calcium-binding protein (CALB3) is a cytosolic protein of molecular weight 9,000 and belongs to a family of calcium-binding proteins that includes calmodulin, parvalbumin, troponin C, and S100 protein. CALB3 is found in the mammalian intestine, placenta, uterus, and kidney. Its exact function is unknown. The intestinal protein is vitamin D-dependent and its expression correlates with calcium transport activity. CALB3 may increase Ca2+ absorption by buffering Ca2+ in the cytoplasm and increase ATP-dependent Ca2+ transport in duodenal basolateral membrane vesicles. In keeping with its role in calcium absorption, concentrations of CALB3 are highest in duodenal villus enterocytes. Expression levels in adult human tissue were substantially lower than in child intestine. Located immediately proximal to DXS43 on chromosome X, CALB3 is a small (5.5 kb) gene comprising 3 exons. There is a possible relationship of CALB3 to hereditary hypophosphatemia.