RAB3 GTPase Activating Protein Subunit 1 (RAB3GAP1)

Members of the RAB3 protein family are implicated in regulated exocytosis of neurotransmitters and hormones. RAB3GAP, which is involved in regulation of RAB3 activity, is a heterodimeric complex consisting a 130-kD catalytic subunit and a 150-kD noncatalytic subunit. RAB3GAP specifically converts active RAB3-GTP to the inactive form RAB3-GDP.

The human RAB3GAP cDNA encodes a 981-amino acid polypeptide. Northern blot analysis showed that RAB3GAP was ubiquitously expressed in human tissues as a 4.5-kb mRNA.p150 did not show GAP activity, and the interaction between p150 and p130 did not alter the activity of p130 or the subcellular distribution of the 2 proteins.