TRPV5 and TRPV6 Calcium-Selective Channels

This chapter reviews the physiological and pathological roles of TRPV5 and TRPV6 and discusses a variety of techniques that have led to a deeper understanding of these channels. It also reviews the identification strategies of TRPV5 and TRPV6 in searches for Ca²⁺absorption channels, as well as specific techniques used to reveal their key features. The epithelial calcium selective channels TRPV5 and TRPV6 are members of the transient receptor potential channel family TRPV subgroup. Intestinal absorption and renal reabsorption of Ca²⁺are similar processes, involving Ca²⁺transport across the epithelia from the luminal side to the blood side. While TRPV5 and TRPV6 represent specialized epithelial Ca²⁺transport proteins, the other four members are nonselective cation channels that serve as sensors and can be activated by physical cues such as heat or tonicity. Ca²⁺imaging, an approach to study Ca²⁺signaling, has been utilized for screening small-molecule inhibitors of TRPV6.