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

MA Fox, JR Sanes - Journal of Comparative Neurology, 2007 - Wiley Online Library
Journal of Comparative Neurology, 2007Wiley Online Library
Abstract 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 …
Abstract
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.
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