RGS7 Attenuates Signal Transduction Through the Gαq Family of Heterotrimeric G Proteins in Mammalian Cells

Abstract: The RGS proteins are a recently discovered family of G protein regulators that have been shown to act as GTPase-activating proteins (GAPs) on the G_αi and G_αq subfamilies of the heterotrimeric G proteins. Here, we demonstrate that RGS7 is a potent GAP in vitro on G_αi1 and G_αo heterotrimeric proteins and that RGS7 acts to down-regulate G_αq-mediated calcium mobilization in a whole-cell assay system using a transient expression protocol. This RGS protein and RGS4 are reported to be expressed predominantly in brain, and in situ hybridization studies have revealed similarities in the regional distribution of RGS and G_αq mRNA expression. Our findings provide further evidence to support a functional role for RGS4 and RGS7 in G_αq-mediated signaling in the CNS.