Assays of RGS3 activation and modulation

Regulator of G-protein signaling (RGS) proteins accelerate the intrinsic GTPase activity of Galpha subunits, terminating G-protein signaling. Although the structure and the downstream effectors of RGS proteins have been investigated extensively, the mechanisms underlying their activation are still largely unexplored. Recent investigations of RGS proteins in intact cells are starting to shed some light on this issue. In particular, the retrovirus-mediated overexpression of individual RGS3 isoforms showed that activation of RGS3s requires Ca2+ binding to an EF-like domain, and such Ca2+ binding promotes the rapid desensitization of Go-mediated inhibition of N-type Ca2+ (N) channels. This article provides detailed information on the use and power of retrovirus-mediated overexpression of RGS proteins in dorsal root ganglion neurons to isolate and identify the mechanisms underlying the initiation of RGS3-dependent inhibitory activity.