TRPV6

TRPV6 is a membrane calcium channel which is responsible for the first step in calcium absorption in the intestine. It was first named CAT1, or ECaC2, and has been described in the intestine in several species, including humans. It is located in the apical brush-border membrane of the intestinal enterocyte where is regulates calcium entry into the cell. It is most abundant in the proximal small intestine (duodenum and jejunum) where calbindin and the calcium-pumping ATPAse are also found. The TRPV6 calcium transporter also found in the human placenta, pancreas and prostate gland and in some species in the kidney where the related channel TRPV5 is strongly expressed.

TRPV6 is a member of the Transient receptor potential family of membrane proteins.

Expression of TRPV6 appears to be vitamin D dependent as it is greatly reduced in animals that do not express the vitamin D receptor. Importantly, vitamin D treatment of colon cancer cells, Caco-2, also increases expression of TRPV6 gene. Vitamin D treatment of these cells also increases transport of calcium, probably via increasing TRPV6 expression.