Figure 1: Ras signaling activity between active (GTP-bound) Cdc42 and inactive (GDP-bound) Cdc42. Guanine nucleotide exchange factors (GEFs) (green square) catalyze the GDP-GTP exchange; and GTPase-activating (GAPs) (yellow square) effector proteins catalyze the inactivation of Ras by stimulating GTP hydrolysis. Downstream signaling pathways involving Ras effector interactions with the Ras-activated state (green circle) in processes such as cell proliferation (green extension) and trafficking (red extension) are also highlighted.