Rho GTPases are important regulators of the actin cytoskeleton and consequently influence the shape and migration of cells. GTPase-activating proteins (GAPs) accelerate the intrinsic rate of GTP hydrolysis of Ras-related proteins. ARHGAP39 (Rho GTPase activating protein 39) is a 1, 083 amino acid nuclear protein that contains one MyTH4 domain, one Rho GAP domain and two WW domains. It is encoded by a gene located on human chromosome 8, which is associated with a variety of diseases and malignancies. ARHGAP39 regulates robo signaling and plays important roles in axon guidance.Synonyms: CrGAP, CrossGAP, Rho GTPase activating protein 39, Vilse