Role of the cytoplasmic protein synaphin in the process of transmitter release

细胞质蛋白突触蛋白在递质释放过程中的作用

基本信息

批准号：
09680760
负责人：
ABE Teruo
金额：
$ 2.3万
依托单位：
Niigata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09680760/
关键词：
Synaphin Transmitter release Syntaxin Synapse シナプスシナ-フィン

项目摘要

Synaphin is a cytosolic protein we first found to be associated with the docking/fusion complex that is critical to transmitter release. The goal of this study was to clarify the function of this protein in the release process. We have obtained following results.(1) Distribution in the brain and tevolutionary conservationTwo isoforms of synaphin (synaphins 1 and 2 : 84% identical) exist in the brain. The two isoforms are distictly distributed in the brain regions such as cerebral cortex, thalamus, cerebellum and amygdaloid., indicating different physiological implications for the isoforms. Synaphins very similar to mammalian ones are present in fish, and an invertebrate nervous system also contains the proteins.(2) FunctionWhen a peptide corresponding to a partial amino acid sequence of synaphin was injected into the presynaptic terminal of the squid giant synapse, transmitter release was rapidly inhibited. This peptide inhibited binding of synaphin to syntaxin but did not affect SNARE interactions, synaptic vesicle docking or calcium channel functions. Thus synaphin/syntaxin interaction is essential for transmitter release. In vitro binding experiments between recombinant SNARE proteins and synaphin show that syntaxin alone binds very little synaphin. However, the synaptic vesicle protein VAMP (synaptobrevin) markedly facilitated syntaxin binding to synaphin. Conversely, synaphin geatly increased the affinity of VAMP to syntaxin. Taken together, these results indicate that synaphin/SNARE interactions play an essential role at a step between synaptic vesicle docking and fusion.

Synaphin是一种胞质蛋白，我们首先发现与对接器释放至关重要的对接/融合复合物有关。这项研究的目的是阐明该蛋白在发行过程中的功能。我们已经获得了以下结果。（1）在大脑中存在脑和扭转性的两种同工型中的分布，并存在于大脑中。这两种同工型分布在大脑区域，例如脑皮质，丘脑，小脑和杏仁核，表明对同工型的生理意义不同。 FISH中存在与哺乳动物非常相似的敏感蛋白，并且无脊椎动物神经系统还包含蛋白质。（2）将与某种氨基酸的肽序列相对应的功能被注射到鳞状巨型突触的突触前末端中，快速抑制了发射剂。该肽抑制了synaphin与语法素的结合，但不影响圈质相互作用，突触囊泡对接或钙通道功能。因此，Synaphin/Syntaxin相互作用对于释放发射机至关重要。重组蛋白质蛋白和synaphin之间的体外结合实验表明，单独的语法结合了很少的synaphin。然而，突触囊泡蛋白鞋面（突触纤维）显着促进了语法与synaphin的结合。相反，Synaphin会增加VAMP对语法素的亲和力。综上所述，这些结果表明，在突触囊泡对接和融合之间的步骤中，synaphin/snare相互作用起着至关重要的作用。