Mode of actions and functions of the Rab3A and SNARE systems in neurotransmitter release

Rab3A 和 SNARE 系统在神经递质释放中的作用模式和功能

基本信息

批准号：
11670118
负责人：
SHIRATAKI Hiromichi
金额：
$ 2.3万
依托单位：
DOKKYO UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11670118/
关键词：
Neurotransmitter Rab3A system SNARE system Small GTPase Rab系 Rab3A SNARE Tomosyn

项目摘要

It has been revealed that the Rab3A, a small GTPase, and SNARE systems are involved in neurotransmitter release. The Rab3A system consists of its target protein, which interacts with the GTP-bound form of Rab3A but not with the GDP-bound form of Rab3A, and its several regulatory proteins. We have identified Rabphilin-3 as a target protein for Rab3A and revealed the possibility that Rabphilin-3 functions as a Ca^<2+>-sensor in the presynapse. On the other hand, available evidence suggests that the SNARE system functions at the downstream of the Rab3A system and is implicated in neurotransmitter release. We have identified Tomosyn as a regulatory protein of the SNARE system. It is possible that Tomosyn is a central player which links between the Rab3A and SNARE systems. However, the mechanism by which the Rab3A system regulates the SNARE system in neurotransmitter release remains to be clarified. Therefore, in this study we attempted to clarify the mechanism. We revealed that there were at least three isoforms of Tomosyn, b-, m-, and s-Tomosyns and that all of the tomosyn isoforms interacted through their C-terminal VAMP-like regions with syntaxin-1 but not with other syntaxin isoforms such as syntaxin-2, -3, and -4. Moreover, we identified a novel syntaxin-1-binding protein. On the basis of its biochemical properties, it was possible that the syntaxin-1-binding protein was a cytoskeleton-related protein. One mole of the syntaxin-1-binding protein bound to about 0.8 mole of syntaxin-1 and the dose giving the half maximal binding of syntaxin-1 to the syntaxin-1-binding protein was about 90 nM.The interaction of the syntaxin-1-binding protein with syntaxin-1 was inhibited by Munc18 in a dose-dependent manner. In future we attempt to purify the syntaxin-1-binding protein, determine its primary structure, and reveal its function in neurotransmitter release.

已经揭示了Rab3a，一个小的GTPase和SNARE系统参与神经递质释放。 RAB3A系统由其靶蛋白组成，该靶蛋白与RAB3A的GTP结合形式相互作用，但与GDP结合形式的Rab3a及其几种调节蛋白相互作用。我们已经将Rabphilin-3鉴定为Rab3a的靶蛋白，并揭示了Rabphilin-3在散发前中的Ca^<2+> - 传感器的可能性。另一方面，可用的证据表明，SNARE系统在RAB3A系统的下游功能，与神经递质释放有关。我们已经确定了Tomosyn是圈套系统的调节蛋白。 Tomosyn可能是在RAB3A和SNARE系统之间链接的中心参与者。但是，RAB3A系统调节神经递质释放中的SNARE系统的机制尚待澄清。因此，在这项研究中，我们试图阐明该机制。我们透露，tomosyn，b-，m-和s-tomosyn至少有三种同工型，并且所有的tomosyn同工型通过其C末端VAMP样区域与Synttaxin-1相互作用，但与其他同型同型同型同种型相互作用，例如syntaxin-2，-3，-3和-4。此外，我们确定了一种新型的Syntaxin-1结合蛋白。在其生化特性的基础上，语法1结合蛋白可能是细胞骨架相关的蛋白。与索引蛋白-1结合约0.8摩尔的一摩尔和统一的剂量和剂量的剂量最大结合的剂量与语法-1结合蛋白的最大结合约为90 nm。大约90 nm。在dose ressent中抑制了语法1-结合蛋白与语法蛋白与语法蛋白1的相互作用。将来，我们试图纯化语法素1结合蛋白，确定其主要结构，并揭示其在神经递质释放中的功能。