TRPV6
Encyclopedia
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
(TRP) family of membrane proteins. Unlike most TRP channels, TRPV6 is selective for Ca2+ ions, similarly to its close homologue, TRPV5
, which is mainly expressed in the kidney, and plays a role in Ca2+ reabsorption.
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.
Calcium channel
A Calcium channel is an ion channel which displays selective permeability to calcium ions. It is sometimes synonymous as voltage-dependent calcium channel, although there are also ligand-gated calcium channels.-Comparison tables:...
which is responsible for the first step in calcium absorption in the intestine
Intestine
In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large 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
Calbindin
Calbindin refers to several calcium-binding proteins. They were originally described as vitamin D-dependent calcium-binding proteins in the intestine and kidney in the chick and mammals...
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
Transient receptor potential
Transient receptor potential channels are a group of ion channels located mostly on the plasma membrane of numerous human and animal cell types. There are about 28 TRP channels that share some structural similarity to each other...
(TRP) family of membrane proteins. Unlike most TRP channels, TRPV6 is selective for Ca2+ ions, similarly to its close homologue, TRPV5
TRPV5
Transient receptor potential cation channel subfamily V member 5 is a protein that in humans is encoded by the TRPV5 gene.TRPV5 is mainly expressed in kidney epithelial cells, where it plays an important role in the reabsorption of Ca2+.. Genetic deletion of TRPV5 in mice leads to Ca2+ loss in the...
, which is mainly expressed in the kidney, and plays a role in Ca2+ reabsorption.
Expression of TRPV6 appears to be vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
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.