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Roles of G-proteins and cytoskeletal porteins in transmitter release.

G 蛋白和细胞骨架蛋白在递质释放中的作用。

基本信息

批准号：
05680683
负责人：
KUMAKURA Konosuke
金额：
$ 1.28万
依托单位：
Sophia University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05680683/
关键词：
Mechanism of Exocytosis Transmitter Release GTP-Binding Proteins Myosin Light Chain Kinase Ca^<2+>-Dependent Release ATP-Dependent Priming Mastoparan Cytoskeletal Proteins ヴォルトマニン

项目摘要

The aim of this research project is to clarify the roles of GTP-binding proteins and cytoskeletal proteins in the mechanism of transmitter release.Previously we have suggested that Go, one of heterotrimeric GTP-binding proteins, negatively regulates Ca^<2+>-dependent release of catecholamine in permeabilized chromaffin cells.We also have suggested a possible involvement of myosin light chain kinase in the mechanism of Ca^<2+>-dependent exocytosis.In the project, we attempted to elucidate the mechanism whereby Ca^<2+>-dependent release is regulated by Go, and by myosin light chain kinase in permeabilized chromaffin cells.We have obtained the following results.1.By use of mastoparan, a peptide known to activate directly GTP-binding proteins, and by use of anti-Go antibodies, we found that the negative regulation by Go is on the process of ATP-dependent priming of exocytosis.This inhibitory Go was suggested to be activated by GAP43, and activation of protein kinase C seemed to stimulate Ca^<2+>-dependent release by abolishing the action of GAP43 on Go.2.We found that myosin light chain kinase is essential for ATP-dependent priming of exocytosis, by use of specific inhibitors of myosin light chain kinase, wortmannin and SM-1.Histochemical studies suggested that the inhibition of myosin light chain kinase inhibits reorganization of cortical F-actin, and thus suggested an important role of cortical F-actin for priming of chromaffin vesicles to the exocytotic site.

本研究的目的是阐明GTP结合蛋白和细胞骨架蛋白在递质释放机制中的作用。在透性化的嗜铬细胞中，肌球蛋白轻链激酶负性调节Ca^<2+>依赖的儿茶酚胺释放，我们还提出了肌球蛋白轻链激酶可能参与Ca^<2+>依赖的细胞内Ca 2+释放的机制。本研究试图阐明Go和肌球蛋白轻链激酶在透性化嗜铬细胞中调节Ca^2+依赖性释放的机制，获得了以下结果：1.通过使用mastoparan（一种已知可直接激活GTP结合蛋白的肽）和使用抗Go抗体，我们发现Go的负调节作用是ATP依赖的胞吐启动过程，这种抑制性Go被GAP 43激活，蛋白激酶C的激活似乎刺激了Ca^<2+>-2.我们发现肌球蛋白轻链激酶对于胞吐作用的ATP依赖性引发是必需的，通过使用肌球蛋白轻链激酶的特异性抑制剂，组织化学研究表明，肌球蛋白轻链激酶的抑制可抑制皮质F-肌动蛋白的重组，从而提示皮质F-肌动蛋白在嗜铬小泡向胞吐位点的启动中起重要作用。