Identification of a Syntaxin-Binding Site on N-type Calcium Channels

Neuron. 1994 Dec;13(6):1303-13. doi: 10.1016/0896-6273(94)90417-0.

Abstract

Immunochemical studies have suggested a tight association of syntaxin with N-type calcium channels. Syntaxin specifically interacts with the fusion proteins containing the cytoplasmic loop (LII-III) between homologous repeats II and III of the alpha 1 subunit of the class B N-type calcium channel (alpha 1B) from rat brain, but not with those of the class A Q-type (alpha 1A) or the class S L-type (alpha 1S) calcium channels. This interaction is mediated by an 87 amino acid sequence (773-859) containing two overlapping predicted helix-loop-helix domains. The 87 amino acid peptide can specifically block binding of native N-type calcium channels to syntaxin, indicating that this binding site is required for stable interaction of these two proteins. Interaction takes place with the C-terminal one-third of syntaxin (residues 181-288), which is thought to be anchored in the presynaptic plasma membrane. Our results suggest a direct interaction between the cytoplasmic domains of these two presynaptic membrane proteins that could have an important role in the targeting and docking of synaptic vesicles near N-type calcium channels, enabling tight structural and functional association of calcium entry sites and neurotransmitter release sites.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Binding Sites
  • Binding, Competitive
  • Brain / ultrastructure
  • Calcium Channels / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / metabolism*
  • Peptides / metabolism
  • Protein Binding
  • Qa-SNARE Proteins
  • Rats
  • Rats, Sprague-Dawley
  • Structure-Activity Relationship
  • omega-Conotoxin GVIA

Substances

  • Calcium Channels
  • Membrane Proteins
  • Peptides
  • Qa-SNARE Proteins
  • omega-Conotoxin GVIA