title: The cytoplasmic domain of rat synaptotagmin I enhances synaptic transmission.
abstract: Synaptotagmin, an integral membrane protein of synaptic vesicles, functions as a calcium sensor in the temporal control of neurotransmitter release. Although synaptotagmin facilitates lipid membrane fusion in biochemical experiments, overexpression of synaptotagmin inhibits neurotransmission. A facilitatory effect of synaptotagmin on synaptic transmission was never observed. To determine whether synaptotagmin may accelerate synaptic transmission in vivo, we injected the cytoplasmic domain of rat synaptotagmin I (CD-syt) into crayfish motor axons and tested the effect of CD-syt on synaptic response. We confirmed that CD-syt accelerates neuromuscular transmission. The injected preparation had larger synaptic potentials with shorter rise time. Experiments with varying calcium concentrations showed that CD-syt increased the maximum synaptic response of the neuromuscular synapses. Further tests on short-term plasticity of neuromuscular synapses revealed that CD-syt increases the release probability of the release-ready vesicles.
authors.affiliation: Department of Biology, York College and Graduate Center, The City University of New York, 94-20 Guy R. Brewer Boulevard, Jamaica, NY, 11451, USA, shua@york.cuny.edu.
authors.forename: Shao-Ying
authors.initials: SY
authors.lastname: Hua
authors.forename: Ali
authors.initials: A
authors.lastname: Syed
authors.forename: Thierry C
authors.initials: TC
authors.lastname: Aupérin
authors.forename: Liang
authors.initials: L
authors.lastname: Tong
mesh_terms: D000818:Animals; D003400:Astacoidea; D003593:Cytoplasm / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology; D005260:Female; D008297:Male; D051381:Rats; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology; D050863:Synaptotagmin I / Q000494:pharmacology*
chemical_list: D050863:Synaptotagmin I