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

Mol Biol Cell. 2002 Aug;13(8):2706-17. doi: 10.1091/mbc.e02-01-0036.


To investigate the molecular interactions of synaptophysin I and vesicle-associated membrane protein 2 (VAMP2)/synaptobrevin II during exocytosis, we have used time-lapse videomicroscopy 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 alpha-latrotoxin, VAMP2 dissociates from synaptophysin I even in the absence of appreciable exocytosis, whereas synaptophysin I 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Exocytosis / physiology*
  • Fluorescence Resonance Energy Transfer*
  • Hippocampus / cytology
  • Hippocampus / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Microscopy, Video
  • Models, Biological
  • Nerve Tissue Proteins / metabolism
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / physiology
  • R-SNARE Proteins
  • Rats
  • Rats, Sprague-Dawley
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism*
  • Spider Venoms / pharmacology
  • Synapses / metabolism*
  • Synaptic Vesicles / metabolism
  • Synaptophysin / genetics
  • Synaptophysin / metabolism*
  • Time Factors


  • Membrane Proteins
  • Nerve Tissue Proteins
  • R-SNARE Proteins
  • Recombinant Fusion Proteins
  • Spider Venoms
  • Synaptophysin
  • alpha-latrotoxin

Grants and funding