Complexins: cytosolic proteins that regulate SNAP receptor function

Cell. 1995 Oct 6;83(1):111-9. doi: 10.1016/0092-8674(95)90239-2.

Abstract

A family of proteins called complexins was discovered that compete with alpha-SNAP, but not synaptotagmin, for SNAP receptor binding. Complexins I and II are highly homologous hydrophilic proteins that are tightly conserved, with 100% identity among mouse, rat, and human complexin II. They are enriched in neurons where they colocalize with syntaxin and SNAP-25; in addition, complexin II is expressed ubiquitously at low levels. Complexins bind weakly to syntaxin alone and not at all to synaptobrevin and SNAP-25, but strongly to the SNAP receptor-core complex composed of these three molecules. They compete with alpha-SNAP for binding to the core complex but not with other interacting molecules, including synaptotagmin I, suggesting that the complexins regulate the sequential interactions of alpha-SNAP and synaptotagmins with the SNAP receptor during exocytosis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Vesicular Transport
  • Amino Acid Sequence
  • Animals
  • Brain Chemistry
  • Calcium / metabolism
  • Calcium-Binding Proteins*
  • Carrier Proteins / metabolism
  • Cytosol / chemistry
  • Exocytosis
  • Gene Expression
  • Hippocampus / cytology
  • Humans
  • Macromolecular Substances
  • Membrane Fusion / physiology*
  • Membrane Glycoproteins / metabolism
  • Membrane Proteins / metabolism
  • Membrane Proteins / physiology*
  • Mice
  • Molecular Sequence Data
  • Nerve Tissue Proteins / chemistry
  • Nerve Tissue Proteins / isolation & purification
  • Nerve Tissue Proteins / metabolism
  • Nerve Tissue Proteins / physiology*
  • Neurons / chemistry
  • R-SNARE Proteins
  • Rats
  • Recombinant Fusion Proteins / metabolism
  • SNARE Proteins
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
  • Species Specificity
  • Synaptic Vesicles / metabolism*
  • Synaptosomal-Associated Protein 25
  • Synaptotagmin I
  • Synaptotagmins
  • Vesicular Transport Proteins*

Substances

  • Adaptor Proteins, Vesicular Transport
  • Calcium-Binding Proteins
  • Carrier Proteins
  • Macromolecular Substances
  • Membrane Glycoproteins
  • Membrane Proteins
  • Nerve Tissue Proteins
  • R-SNARE Proteins
  • Recombinant Fusion Proteins
  • SNAP25 protein, human
  • SNARE Proteins
  • SYT1 protein, human
  • Snap25 protein, mouse
  • Snap25 protein, rat
  • Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
  • Synaptosomal-Associated Protein 25
  • Synaptotagmin I
  • Syt1 protein, mouse
  • Syt1 protein, rat
  • Vesicular Transport Proteins
  • complexin I
  • complexin II
  • Synaptotagmins
  • Calcium

Associated data

  • GENBANK/U35098
  • GENBANK/U35099
  • GENBANK/U35100
  • GENBANK/U35101