The accessory helix of complexin functions by stabilizing central helix secondary structure Academic Article uri icon


MeSH Major

  • Adaptor Proteins, Vesicular Transport
  • Cell Membrane
  • Nerve Tissue Proteins


  • The presynaptic protein complexin (CPX) is a critical regulator of synaptic vesicle fusion, but the mechanisms underlying its regulatory effects are not well understood. Its highly conserved central helix (CH) directly binds the ternary SNARE complex and is required for all known CPX functions. The adjacent accessory helix (AH) is not conserved despite also playing an important role in CPX function, and numerous models for its mechanism have been proposed. We examined the impact of AH mutations and chimeras on CPX function in vivo and in vitro using C. elegans. The mouse AH fully restored function when substituted into worm CPX suggesting its mechanism is evolutionarily conserved. CPX inhibitory function was impaired when helix propagation into the CH was disrupted whereas replacing the AH with a non-native helical sequence restored CPX function. We propose that the AH operates by stabilizing CH secondary structure rather than through protein or lipid interactions.

publication date

  • November 10, 2014



  • Academic Article



  • eng

PubMed Central ID

  • PMC4270070

Digital Object Identifier (DOI)

  • 10.7554/eLife.04553

PubMed ID

  • 25383924

Additional Document Info


  • 3


  • November