Expression and characterization of a trpl homolog from rat.

Mammalian homologues of the Drosophila trp/trpl-gene-family code for "Ca(2+)-store-operated" channels. Here we describe the cloning and expression of a trp/trpl homologous gene from rat brain. The clone is named Rtrp3 because of its high homology to the recently described Htrp3 (Zhu et al (1996) Cell 85:661-671). Expression of Rtrp3 in the mammalian COS-1 cell line leads to 100% increase of capacitative Ca2+ entry as compared to the controls. This capacitative calcium entry can be completely blocked with La3+ (10 microM). We conclude that Rtrp3, a new member of the growing family of trp/trpl homologues in mammalians, is involved in "Ca(2+)-store-operated" Ca2+ entry into the cell.