Epithelial calcium channels: from identification to function and regulation

The epithelial calcium channels TRPV5 and TRPV6 have been studied extensively in the epithelial tissues controlling Ca(2+) homeostasis and exhibit a range of distinctive properties that distinguish them from other transient receptor potential (TRP) channels. These two novel members of the superfamily of TRP channels were cloned from vitamin D-responsive epithelia: kidney, small intestine and placenta, and identified subsequently in tissues like pancreas, bone and prostate. This review addresses the unique properties of these highly Ca(2+)-selective channels and highlights their implications for the process of transepithelial Ca(2+) transport.