Synaptotagmin I and II are present in distinct subsets of central synapses

J Comp Neurol. 2007 Jul 10;503(2):280-96. doi: 10.1002/cne.21381.


Synaptotagmin 1 and 2 (syt 1, syt 2) are synaptic vesicle-associated membrane proteins that act as calcium sensors for fast neurotransmitter release from presynaptic nerve terminals. Here we show that widely used monoclonal antibodies, mab 48 and znp-1, stain nerve terminals in multiple species and, in mouse, recognize syt 1 and syt 2, respectively. With these antibodies, we examined the synaptic localization of these synaptotagmin isoforms in the mouse central nervous system. Syt 1 and syt 2 are localized predominantly to different subsets of synapses in retina, hippocampus, cerebellum, and median nucleus of the trapezoid body (MNTB). In the MNTB, syt 1 and syt 2 are present in different presynaptic terminals on the same postsynaptic principal neuron. In retina, horizontal and OFF-bipolar cell terminals contain syt 2, whereas most other terminals contain syt 1. Syt 1 localization in the immature retina resembles that seen in adult; however, syt 2 localization appears strikingly different at perinatal ages and continues to change dramatically prior to eye opening. For example, starburst amacrine cells, which lack syt 2 in adult retina, transiently express syt 2 during the first 2 postnatal weeks. In addition to differences in spatial and temporal distribution, species-specific differences in synaptotagmin localization were observed in retina and cerebellum. The cell-, temporal-, and species-specific expression of synaptotagmin isoforms suggests that each may have distinct functions in neurotransmitter release.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies, Monoclonal / metabolism
  • Central Nervous System / cytology
  • Central Nervous System / metabolism*
  • Cerebellum / cytology
  • Cerebellum / metabolism
  • Chick Embryo
  • Hippocampus / cytology
  • Hippocampus / metabolism
  • Immunohistochemistry
  • Mice
  • Photoreceptor Cells / metabolism
  • Presynaptic Terminals / metabolism*
  • Protein Isoforms
  • Retina / cytology
  • Retina / metabolism*
  • Species Specificity
  • Synaptotagmin I / metabolism*
  • Synaptotagmin II / metabolism*
  • Tissue Distribution
  • Vertebrates
  • Zebrafish


  • Antibodies, Monoclonal
  • Protein Isoforms
  • Synaptotagmin I
  • Synaptotagmin II