RAB3GAP1

Catalytic subunit of the Rab3 GTPase-activating (Rab3GAP) complex composed of RAB3GAP1 and RAB3GAP2, which accelerates the otherwise slow GTP hydrolysis catalyzed by Rab proteins. Has GTPase-activating protein (GAP) activity towards various Rab3 subfamily members (RAB3A, RAB3B, RAB3C and RAB3D), RAB5A and RAB43. Additionally, it has guanine nucleotide exchange factor (GEF) activity towards RAB18, promoting GDP release from RAB18 and the conversion of inactive RAB18-GDP to the active form RAB18-GTP. Recruits and stabilizes RAB18 at the cis-Golgi membrane in fibroblasts where RAB18 is most likely activated. Also involved in RAB18 recruitment at the endoplasmic reticulum (ER) membrane where it maintains proper ER structure. Required for normal eye and brain development. May participate in neurodevelopmental processes such as cell proliferation, migration and differentiation before synapse formation, and is involved in regulating non-synaptic vesicular release of neurotransmitters..

Function from UniProtKB (Q15042), read 2026-09-23. CC BY 4.0.