Small G proteins of the Rab family are regulators of intracellular vesicle traffic. Their rate of GTP hydrolysis is enhanced by specific GTPase-activating proteins (GAPs) that switch G proteins to their inactive form []. Rab3GAP1 (catalytic subunit) has been shown to form a heterodimeric complex with Rab3GAP2 (the regulatory subunit), and this complex acts as a guanosine nucleotide exchange factor for Rab3 subfamily (RAB3A, RAB3B, RAB3C and RAB3D). Rab3GAP complex may participate in neurodevelopmental processes such as proliferation, migration and differentiation before synapse formation, and non-synaptic vesicular release of neurotransmitters [, ]. It also activates Rab18 and promotes autolysosome maturation through the Vps34 Complex I [].Mutations in the Rab3GAP1/2 gene cause Warburg micro syndrome (WMS), a hereditary autosomal neuromuscular disorder [].
