查看文章

Cell signalling requires efficient Ca²⁺ mobilization from intracellular stores through Ca²⁺ release channels, as well as predicted counter-movement of ions across the sarcoplasmic/endoplasmic reticulum membrane to balance the transient negative potential generated by Ca²⁺ release^,,,,,,. Ca²⁺ release channels were cloned more than 15 years ago^,, whereas the molecular identity of putative counter-ion channels remains unknown. Here we report two TRIC (trimeric intracellular cation) channel subtypes that are differentially expressed on intracellular stores in animal cell types. TRIC subtypes contain three proposed transmembrane segments, and form homo-trimers with a bullet-like structure. Electrophysiological measurements with purified TRIC preparations identify a monovalent cation-selective channel. In TRIC-knockout mice suffering embryonic cardiac failure, mutant cardiac myocytes show severe …