Interaction of SNARE complexes with P/Q-type calcium channels in rat cerebellar synaptosomes

Nicole Martin-Moutot, Nathalie Charvin, Christian Leveque, Kazuki Sato, Tei Ich Nishiki, Shunji Kozaki, Masami Takahashi, Michael Seagar

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115 Citations (Scopus)


P- and Q-type calcium channels, which trigger rapid neurotransmitter release at many mammalian synapses, are blocked by ω-conotoxin MVIIC. 125I-ω-Conotoxin MVIIC binding to rat cerebellar synaptosomes was not displaced by ω-conotoxins GVIA or MVIIA (K(i) > 1 μM), which are selective for N-type calcium channels. Solubilized 125I-ω-conotoxin MVIIC receptors were specifically recognized by antibodies directed against α1A calcium channel subunits, proteins known to constitute a pore with P/Q-like channel properties. Antibodies against syntaxin 1, SNAP 25, and VAMP 2 (synaptobrevin) each immunoprecipitated a similar fraction (20-40%) of ω- conotoxin MVIIC receptors. Immunoprecipitation was not additive, suggesting that heterotrimeric (SNARE) complexes containing these three proteins interact with P/Q-type calcium channels. Immobilized monoclonal anti-syntaxin antibodies retained α1A calcium channel subunits of 220, 180 and 160 kDa monitored by immunoblotting with site directed antibodies. Synaptotagmin was detected in channel-associated complexes, but not synaptophysin, Rab 3A nor rat cysteine string protein. Trimeric SNARE complexes are implicated in calcium-dependent exocytosis, a process thought to be regulated by synaptotagmin. Our results indicate that these proteins interact with P/Q- type calcium channels, which may optimize their location within domains of calcium influx.

Original languageEnglish
Pages (from-to)6567-6570
Number of pages4
JournalJournal of Biological Chemistry
Issue number12
Publication statusPublished - Mar 22 1996

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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