Activated Gαq family members induce Rho GTPase activation and Rho-dependent actin filament assembly

AbstractRho GTPase is required for actin filament assembly and serum response element (SRE)-dependent gene transcription. Certain G protein-coupled receptors (GPCRs) induce Rho-dependent responses, but the intermediary signaling steps are poorly understood. The heterotrimeric Gα12 family can induce Rho-dependent responses. In contrast, there are conflicting reports on the role of the Gαq family in Rho signaling. We report that expression of activated Gαq members, or activation of endogenous Gαq via GPCR stimulation, induces SRE reporter activation via Rho, and increased GTP-Rho levels. Moreover, microinjection of activated Gαq in fibroblasts induces actin stress fiber formation via Rho. Gαq functionally cooperates with Lbc Rho guanine nucleotide exchange factor. Overall, these findings indicate that Gαq family signals are sufficient to induce Rho-dependent cellular responses