RACGAP1 belongs to a subtype of Rho GTPases in the Ras superfamily of small G proteins which destroy activated forms of Rho GTPases and stimulate GTP hydrolysis.
There are 3 subtypes of Rho GTPases in the Ras superfamily of small G proteins: RHO (see MIM 165370), RAC (see RAC1; MIM 602048), and CDC42 (MIM 116952). GTPase-activating proteins (GAPs) bind activated forms of Rho GTPases and stimulate GTP hydrolysis. 
