Fluorescence resonance energy transfer detection of synaptophysin I and vesicle-associated membrane protein 2 interactions during exocytosis from single live synapses

Maria Pennuto, David Dunlap, Andrea Contestabile, Fabio Benfenati, Flavia Valtorta

Research output: Contribution to journalArticlepeer-review

Abstract

To investigate the molecular interactions of synaptophysin I and vesicle-associated membrane protein 2 (VAMP2)/synaptobrevin II during exocytosis, we have used time-lapse videomicros-copy to measure fluorescence resonance energy transfer in live neurons. For this purpose, fluorescent protein variants fused to synaptophysin I or VAMP2 were expressed in rat hippocampal neurons. We show that synaptophysin I and VAMP2 form both homo- and hetero-oligomers on the synaptic vesicle membrane. When exocytosis is stimulated with α-latrotoxin, VAMP2 dissociates from synaptophysin I even in the absence of appreciable exocytosis, whereas synaptophysin 1 oligomers disassemble only upon incorporation of the vesicle with the plasma membrane. We propose that synaptophysin I has multiple roles in neurotransmitter release, regulating VAMP2 availability for the soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex and possibly participating in the late steps of exocytosis.

Original languageEnglish
Pages (from-to)2706-2717
Number of pages12
JournalMolecular Biology of the Cell
Volume13
Issue number8
DOIs
Publication statusPublished - Aug 2002

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

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