Two sites of action for synapsin domain E in regulating neurotransmitter release

Nat Neurosci. 1998 May;1(1):29-35. doi: 10.1038/229.


Synapsins, a family of synaptic vesicle proteins, have been shown to regulate neurotransmitter release; the mechanism(s) by which they act are not fully understood. Here we have studied the role of domain E of synapsins in neurotransmitter release at the squid giant synapse. Two squid synapsin isoforms were cloned and found to contain a carboxy (C)-terminal domain homologous to domain E of the vertebrate a-type synapsin isoforms. Presynaptic injection of a peptide fragment of domain E greatly reduced the number of synaptic vesicles in the periphery of the active zone, and increased the rate and extent of synaptic depression, suggesting that domain E is essential for synapsins to regulate a reserve pool of synaptic vesicles. Domain E peptide had no effect on the number of docked synaptic vesicles, yet reversibly inhibited and slowed the kinetics of neurotransmitter release, indicating a second role for synapsins that is more intimately associated with the release process itself. Thus, synapsin domain E is involved in at least two distinct reactions that are crucial for exocytosis in presynaptic terminals.

Publication types

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

MeSH terms

  • Amino Acid Sequence / genetics
  • Animals
  • Cloning, Molecular
  • Decapodiformes
  • Isomerism
  • Kinetics
  • Molecular Sequence Data
  • Neurotransmitter Agents / antagonists & inhibitors
  • Neurotransmitter Agents / metabolism*
  • Peptide Fragments / genetics*
  • Peptide Fragments / physiology*
  • Synapsins / genetics*
  • Synapsins / physiology*
  • Synaptic Vesicles / physiology


  • Neurotransmitter Agents
  • Peptide Fragments
  • Synapsins