INTERACTION OF A SYNAPTOBREVIN (VAMP)-SYNTAXIN COMPLEX WITH PRESYNAPTIC CALCIUM CHANNELS

Nerve terminal protein complexes implicated in exocytosis mere examine d by immune-isolation from rat brain synaptosomes. Immunoprecipitation with anti-syntaxin or anti-VAMP antibodies revealed a syntaxin-SNAP25 -VAMP-synaptotagmin complex. Anti-VAMP antibodies also trapped a disti nct VAMP-synaptophysin complex. A similar fraction (about 70%) of N-ty pe calcium channels ([I-125]omega conotoxin GVIA receptors), was immun oprecipitated by either anti-syntaxin or anti-VAMP antibodies, but not by anti-synaptophysin antibodies (<4%). The majority of N- but not L- type calcium channels ([H-3]PN200-110 receptors), appear to be associa ted with a synaptic vesicle prefusion complex.