title: Complexin maintains vesicles in the primed state in C. elegans.
abstract: BACKGROUND
  Complexin binds the SNARE complex at synapses and regulates exocytosis, but genetic studies indicate contradictory roles: in flies it predominantly inhibits synaptic vesicle fusion, whereas in mice it promotes evoked responses.
  
  
  RESULTS
  Here we characterize the complexin mutant in the nematode Caenorhabditis elegans and reveal bipolar functions in neurotransmission: complexin inhibits spontaneous fusion of synaptic vesicles but is also essential for evoked responses. Complexin mutants exhibit a doubling of vesicle fusion in the absence of extracellular calcium. Even more profoundly, mutants exhibit an almost complete loss of evoked responses, and current amplitudes are reduced by 94%. One possible interpretation is that complexin is required for the stabilization of docked vesicles and that, in its absence, vesicles may fuse or undock from the plasma membrane. Consistent with this hypothesis, docked synaptic vesicles are reduced by 70% in complexin-1 mutants.
  
  
  CONCLUSIONS
  These data suggest that the main function of complexin is to maintain the docked state both by inhibiting fusion and by promoting priming.
authors.affiliation: Howard Hughes Medical Institute and Department of Biology, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Hobson
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: Shigeki
authors.initials: S
authors.lastname: Watanabe
authors.forename: Erik M
authors.initials: EM
authors.lastname: Jorgensen
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D005089:Exocytosis; D005786:Gene Expression Regulation / Q000502:physiology*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D050600:SNARE Proteins / Q000235:genetics / Q000378:metabolism; D013572:Synaptic Vesicles / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D050600:SNARE Proteins; C095992:complexin I