This family is the probable catalytic subunit of the GTPase activating protein that has specificity for Rab3 subfamily (RAB3A, RAB3B, RAB3C and RAB3D). It is likely to convert active Rab3-GTP to the inactive form Rab3-GDP. Rab3 proteins are involved in regulated exocytosis of neurotransmitters and hormones. The Rab3 GTPase-activating complex is a heterodimer composed of RAB3GAP and RAB3-GAP150. This complex interacts with DMXL2 [1,2].

1: Localization of the Rab3 small G protein regulators in nerve terminals and their involvement in Ca2+-dependent exocytosis. Oishi H, Sasaki T, Nagano F, Ikeda W, Ohya T, Wada M, Ide N, Nakanishi H, Takai Y; J Biol Chem. 1998;273:34580-34585. PMID:9852129

2: Mutations of the catalytic subunit of RAB3GAP cause Warburg Micro syndrome. Aligianis IA, Johnson CA, Gissen P, Chen D, Hampshire D, Hoffmann K, Maina EN, Morgan NV, Tee L, Morton J, Ainsworth JR, Horn D, Rosser E, Cole TR, Stolte-Dijkstra I, Fieggen K, Clayton-Smith J, Megarbane A, Shield JP, Newbury-Ecob R, Dobyns WB, Graham JM Jr, Kjaer KW, Warburg M, Bond J, Trembath RC, Harris LW, Takai Y, Mundlos S, Tannahill D, Woods CG, Maher ER; Nat Genet. 2005;37:221-223. PMID:15696165