Characterizing the Role of RGS5 in the Regulation of Vascular Smooth Muscle Cell Function

Regulators of G-protein signaling (RGS) modulate G-protein coupled receptor (GPCR) activity in vascular smooth muscle cells (VSMCs). One such protein, RGS5, has been shown to have selective expression in VSMCs and pericytes, and can inhibit signaling from Gαq and Gαi subunits. Using an RGS5 knockout model, we assessed the functional effect of RGS5 in the constriction and dilation of resistance arterioles. Furthermore, we examined the intracellular lipid interaction of RGS proteins to identify the determinants regulating the biologic function of RGS5. Surprisingly, loss of RGS5 function in mesenteric arterioles had no effect on constriction and dilation of resistance arterioles. Cultured VSMCs showed increased basal ERK1/2 phosphorylation and increased VASP signaling in response to SNP treatment in RGS5KO VSMCs as compared to wild type controls, with no effect on cell proliferation. These data suggest RGS5 may integrate multiple intracellular pathways with competing effects on VSMC contraction.%%%%MAST