Ras GTPase Activating Protein 1 (RASA1)

RAS p21 protein activator 1 is a 120-kDa cytosolic human protein that provides two principal activities:Inactivation of Ras from its active GTP-bound form to its unactive GDP-bound form by enhancing the endogenous GTPase activity of Ras, via its C-terminal GAP domain Mitogenic signal transmission towards downstream interacting partners through its N-terminal SH2-SH3-SH2 domains. The protein is located in the cytoplasm and is part of the GAP1 family of GTPase-activating proteins. The gene product stimulates the GTPase activity of normal RAS p21 but not its oncogenic counterpart. Acting as a suppressor of RAS function, the protein enhances the weak intrinsic GTPase activity of RAS proteins resulting in the inactive GDP-bound form of RAS, thereby allowing control of cellular proliferation and differentiation.