srGAP3 (SLIT ROBO Rho GTPase-activating protein 3) is a GTPase activating protein (GAP) for the small G protein Rac. It has a putative role in attenuating Rac1 signalling in neurons. srGAP3 is thought to act downstream of the Slit-Robo pathway, which regulates neuronal migration and axonal branching, and play an important role in axonal regeneration after axotomy. It also plays a putative role in severe mental retardation.