TRPV6
TRPV6 is a membrane calcium channel which is particularly involved in the first step in calcium absorption in the intestine.
Nomenclature
When first discovered it was named CAT1, or ECaC2. The name TRPV6 was confirmed in 2005.
TRPV6 is a member of the transient receptor potential (TRP) family of membrane proteins. Unlike most TRP channels, TRPV6 is selective for Ca2+ ions, a property shared with its close homologue, TRPV5, which is mainly expressed in the kidney and plays a role in renal Ca2+ reabsorption.
Expression
TRPV6 expression has been described in the intestine in several species, including humans. The protein is located in the apical brush-border membrane of the intestinal enterocyte where it regulates calcium entry into the cell. It is most abundant in the proximal small intestine (duodenum and jejunum), along with the other calcium transport proteins, calbindin and the calcium-pumping ATPase, PMCA1. 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.