RhoGAP-FF1 is the FF domain of the Rho GTPase activating proteins (GAPs). These are the key proteins that make the switch between the active guanosine-triphosphate-bound form of Rho guanosine triphosphatases (GTPases) and the inactive guanosine-diphosphate-bound form. Rho guanosine triphosphatases (GTPases) are a family of proteins with key roles in the regulation of actin cytoskeleton dynamics. The RhoGAP-FF1 region contains the FF domain that has been implicated in binding to the transcription factor TFII-I; and phosphorylation of Tyr308 within the first FF domain inhibits this interaction. The RhoGAPFF1 domain constitutes the first solved structure of an FF domain that lacks the first of the two highly conserved Phe residues, but the substitution of Phe by Tyr does not affect the domain fold [1].

1: NMR structural studies on human p190-A RhoGAPFF1 revealed that domain phosphorylation by the PDGF-receptor alpha requires its previous unfolding. Bonet R, Ruiz L, Aragon E, Martin-Malpartida P, Macias MJ; J Mol Biol. 2009;389:230-237. PMID:19393245