Synaptotagmin I- and II-deficient PC12 cells exhibit calcium-independent, depolarization-induced neurotransmitter release from synaptic-like microvesicles

FEBS Lett. 1995 May 15;364(3):328-34. doi: 10.1016/0014-5793(95)00419-a.


Synaptotagmin I- and II-deficient PC12 cells (Shoji-Kasai et al. [1]) were used to compare the role of this protein in the calcium-dependent exocytosis of secretory granules and synaptic-like microvesicles (SLMVs). While neither catecholamine nor protein secretion from secretory granules were altered, the depolarization-induced acetylcholine release from SLMVs was no longer calcium-dependent. We propose that within the exocytotic process of SLMVs, there exist two depolarization-induced steps. One is calcium-dependent and no longer present in synaptotagmin I- and II-deficient cells. The other is induced by depolarization, does not require calcium, and suffices to trigger neurotransmitter release from SLMVs in synaptotagmin I- and II-deficient PC12 cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / metabolism
  • Action Potentials
  • Animals
  • Calcium / pharmacology*
  • Calcium-Binding Proteins*
  • Centrifugation, Density Gradient
  • Choline / metabolism
  • Cytoplasmic Granules / metabolism
  • Exocytosis
  • Membrane Glycoproteins / deficiency
  • Membrane Glycoproteins / physiology*
  • Nerve Tissue Proteins / deficiency
  • Nerve Tissue Proteins / physiology*
  • Neurotransmitter Agents / metabolism*
  • PC12 Cells
  • Rats
  • Synaptic Vesicles / metabolism*
  • Synaptotagmin I
  • Synaptotagmin II
  • Synaptotagmins
  • Tritium


  • Calcium-Binding Proteins
  • Membrane Glycoproteins
  • Nerve Tissue Proteins
  • Neurotransmitter Agents
  • Synaptotagmin I
  • Synaptotagmin II
  • Syt1 protein, rat
  • Syt2 protein, rat
  • Tritium
  • Synaptotagmins
  • Choline
  • Acetylcholine
  • Calcium