Tetanus and botulinum-B Neurotoxins Block Neurotransmitter Release by Proteolytic Cleavage of Synaptobrevin

Nature. 1992 Oct 29;359(6398):832-5. doi: 10.1038/359832a0.

Abstract

Clostridial neurotoxins, including tetanus toxin and the seven serotypes of botulinum toxin (A-G), are produced as single chains and cleaved to generate toxins with two chains joined by a single disulphide bond (Fig. 1). The heavy chain (M(r) 100,000 (100K)) is responsible for specific binding to neuronal cells and cell penetration of the light chain (50K), which blocks neurotransmitter release. Several lines of evidence have recently suggested that clostridial neurotoxins could be zinc endopeptidases. Here we show that tetanus and botulinum toxins serotype B are zinc endopeptidases, the activation of which requires reduction of the interchain disulphide bond. The protease activity is localized on the light chain and is specific for synaptobrevin, an integral membrane protein of small synaptic vesicles. The rat synaptobrevin-2 isoform is cleaved by both neurotoxins at the same single site, the peptide bond Gln 76-Phe 77, but the isoform synaptobrevin-1, which has a valine at the corresponding position, is not cleaved. The blocking of neurotransmitter release of Aplysia neurons injected with tetanus toxin or botulinum toxins serotype B is substantially delayed by peptides containing the synaptobrevin-2 cleavage site. These results indicate that tetanus and botulinum B neurotoxins block neurotransmitter release by cleaving synaptobrevin-2, a protein that, on the basis of our results, seems to play a key part in neurotransmitter release.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Aplysia
  • Botulinum Toxins / metabolism*
  • Botulinum Toxins / pharmacology*
  • Membrane Proteins / metabolism*
  • Metalloendopeptidases / metabolism*
  • Molecular Sequence Data
  • Nerve Tissue Proteins / metabolism*
  • Neurons / drug effects
  • Neurons / physiology*
  • Neurotoxins / pharmacology*
  • Peptide Fragments / isolation & purification
  • R-SNARE Proteins
  • Substrate Specificity
  • Synaptic Transmission / drug effects*
  • Synaptic Vesicles / drug effects*
  • Synaptic Vesicles / physiology
  • Tetanus Toxin / metabolism*
  • Tetanus Toxin / pharmacology*

Substances

  • Membrane Proteins
  • Nerve Tissue Proteins
  • Neurotoxins
  • Peptide Fragments
  • R-SNARE Proteins
  • Tetanus Toxin
  • Metalloendopeptidases
  • zinc-endopeptidase, tetanus neurotoxin
  • Botulinum Toxins

Grant support