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Synaptotagmin I and II are present in distinct subsets of central synapses
Author(s) -
Fox Michael A.,
Sanes Joshua R.
Publication year - 2007
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.21381
Subject(s) - synaptotagmin 1 , biology , synaptotagmin i , retina , synaptic vesicle , neuroscience , postsynaptic potential , neurotransmitter , cerebellum , gene isoform , microbiology and biotechnology , nucleus , central nervous system , biochemistry , vesicle , receptor , gene , membrane
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. J. Comp. Neurol. 503:280–296, 2007. © 2007 Wiley‐Liss, Inc.