RasGAP functions as an enhancer of the hydrolysis of GTP that is bound to Ras-GTPases. Proteins having a RasGAP domain include p120GAP, IQGAP, Rab5-activating protein 6, and Neurofibromin, among others. Although the Rho (Ras homolog) GTPases are most closely related to members of the Ras family, RhoGAP and RasGAP exhibit no similarity at their amino acid sequence level. RasGTPases function as molecular switches in a large number of signaling pathways. They are in the on state when bound to GTP, and in the off state when bound to GDP. The RasGAP domain speeds up the hydrolysis of GTP in Ras-like proteins acting as a negative regulator.