Activated Galphaq family members induce Rho GTPase activation and Rho-dependent actin filament assembly.
Rho 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 Galpha12 family can induce Rho-dependent responses. In contrast, there are conflicting reports on the role of the Galphaq family in Rho signaling. We report that expression of activated Galphaq members, or activation of endogenous Galphaq via GPCR stimulation, induces SRE reporter activation via Rho, and increased GTP-Rho levels. Moreover, microinjection of activated Galphaq in fibroblasts induces actin stress fiber formation via Rho. Galphaq functionally cooperates with Lbc Rho guanine nucleotide exchange factor. Overall, these findings indicate that Galphaq family signals are sufficient to induce Rho-dependent cellular responses.
Dutt
Parmesh
P
Physiology Department, 136 Harrison Avenue, Tufts University School of Medicine, Boston, MA 02111, USA.
Kjoller
Lars
L
Giel
Maryann
M
Hall
Alan
A
Toksoz
Deniz
D
D016475:3T3 Cells; D000199:Actins / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D004789:Enzyme Activation; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D019204:GTP-Binding Proteins / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D051379:Mice; D011956:Receptors, Cell Surface / Q000378:metabolism
D000199:Actins; D011956:Receptors, Cell Surface; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D020962:Heterotrimeric GTP-Binding Proteins