Background of the antigen
Rab proteins belong to the Ras small GTPase superfamily. The GTP-binding Rab3 subfamily has four known isoforms: 3A, 3B, 3C and 3D. These proteins are expressed in the highest concentration in the brain and endocrine tissues and are involved in regulated exocytosis of hormones and neurotransmitters. Specifically Rab3's are thought to play a role in presynaptic vesicle trafficking and priming.