Regulator of G-protein signaling 5 （RGS5） binds directly to activated G alpha subunits and act as GTPase-activating proteins （GAPs） in order to weaken and/or modulate hormone and neurotransmitter receptor-initiated signaling by both G alpha-GTP and G beta gamma. Vascular endothelial cells express the RGS protein RGS5， where it correlates with capillary morphogenesis， consequently rendering it a candidate gene involved in capillary growth， angiogenesis， and also possibly the pathophysiology of stroke.
