A VAMP-BINDING PROTEIN FROM APLYSIA REQUIRED FOR NEUROTRANSMITTER RELEASE

Before the fusion of synaptic vesicles with the plasma membrane, a pro tein complex is thought to form between VAMP-an integral membrane prot ein of the vesicle-and two proteins associated with the plasma membran e, SNAP-25 and syntaxin. The yeast two-hybrid interaction cloning syst em has now been used to identify additional proteins from Aplysia that interact directly with VAMP. A 33-kilodalton membrane protein, termed VAP-33 (VAMP-associated protein of 33 kilodaltons), was identified wh ose corresponding messenger RNA was detected only in the central nervo us system and the gill of Aplysia. Presynaptic injection of antibodies specific for VAP-33 inhibited synaptic transmission, which suggests t hat VAP-33 is required for the exocytosis of neurotransmitter.