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

• 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

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.

Synphin是一种胞质蛋白，我们首次发现它与对接/融合复合体有关，而对接/融合复合体对递质释放至关重要。这项研究的目的是阐明该蛋白在释放过程中的功能。我们获得了以下结果：(1)脑内分布与进化保守脑内存在两种不同类型的突触蛋白(突触蛋白1和突触蛋白2：84%相同)。这两种异构体在大脑皮层、丘脑、小脑和杏仁核等脑区均有不同的分布，表明这两种异构体具有不同的生理意义。与哺乳动物非常相似的突触素存在于鱼类中，无脊椎动物的神经系统中也含有这些蛋白质。(2)功能当将与突触素的部分氨基酸序列相对应的多肽注入鱿鱼巨型突触的突触前末端时，递质释放迅速受到抑制。该肽抑制突触素与突触素的结合，但不影响SNARE相互作用、突触小泡停靠或钙通道功能。因此，突触素/合成素的相互作用对递质的释放至关重要。重组SNARE蛋白与突触素的体外结合实验表明，单靠突触素结合的突触素很少。然而，突触囊泡蛋白VAMP(Synaptobrevin)显著促进了突触蛋白与突触蛋白的结合。相反，突触素可显著增加VAMP对突触素的亲和力。综上所述，这些结果表明，突触素/SNARE相互作用在突触小泡对接和融合之间起着至关重要的作用。

项目成果

T.Abe: "The domain of synaphin/complexin reguired for SNARE binding" Journal of general physiology. 110. 27a- (1997)

T.Abe：“SNARE 结合所需的突触蛋白/复合蛋白的结构域”普通生理学杂志。

T.Ishizuka et al: "Distinct regional distribution in the brain of messenger RNAs for the two isoformas of synaphin associated with the docking/fusion complex." Neuroscience. vol.88, No.1. 295-306 (1999)

T.Ishizuka 等人：“与对接/融合复合物相关的突触蛋白的两种异构体的信使 RNA 在大脑中存在明显的区域分布。”

H.Tokumaru: "Synaphin/complexin is a critical protein in neurotransmitter release" Journal of general physiology. 110. 26a- (1997)

H.Tokumaru：“突触蛋白/复合蛋白是神经递质释放中的关键蛋白质”《普通生理学杂志》。

T.Ishizuka et al: "Molecular cloning of synaphins/complexins, cytosolic proteins involved in transmitter release, in the electric organ of an electric ray (Narke japonica)." Neuroscience Letters. vol.232 No.1. 107-110 (1997)

T.Ishizuka 等人：“在电鳐（Narke japonica）的电器官中，突触蛋白/复合蛋白、参与递质释放的胞质蛋白的分子克隆。”

M.Yamada et al.: "Immunohistochemical distribution of the two isoforms of synaphin/complexin involved in neurotransmitter release : localization at the distinct CNS regions and synaptic types." Neuroscience. (in press). (1999)

M.Yamada 等人：“参与神经递质释放的两种突触蛋白/复合蛋白亚型的免疫组织化学分布：定位在不同的中枢神经系统区域和突触类型。”