This domain corresponds to the C-terminal region of the catalytic subunit of the GTPase activating protein that has specificity for Rab3 subfamily and converts active Rab3-GTP to the inactive form Rab3-GDP. Rab3 proteins are involved in regulated exocytosis of neurotransmitters and hormones [1,2].

1: Biochemical characterization of Rab3-GTPase-activating protein reveals a mechanism similar to that of Ras-GAP. Clabecq A, Henry JP, Darchen F; J Biol Chem. 2000;275:31786-31791. PMID:10859313

2: Isolation and characterization of a GTPase activating protein specific for the Rab3 subfamily of small G proteins. Fukui K, Sasaki T, Imazumi K, Matsuura Y, Nakanishi H, Takai Y; J Biol Chem. 1997;272:4655-4658. PMID:9030515