Phosphoinositide metabolism in transmembrane signalling

跨膜信号传导中的磷酸肌醇代谢

基本信息

批准号：
62480452
负责人：
TAKAI Yoshimi
金额：
$ 3.97万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1988
项目状态：
已结题

项目摘要

It is well established that many extracellular signals elicit the receptor-linked phosphoinositide turnover and thereby induce both Ca^<2+> mobilization and protein kinase C activation. The mechanisms of signalling from the cell surface receptors to the phospholipase C have not been clarified. In this research project, we have investigated the roles and actions of GTP-binding proteins (G proteins) in these transmembrane signalling mechanisms. First, we have purified and characterized the synaptic membrane phospholipase C. We have also separated multiple G proteins with Mr values of about 20.000 (small Mr G proteins) from several tissues including cerebrum, purified and characterized two novel G proteins designated as smg p25A and smg p21, in addition to c-Ki-ras and rho proteins. It has been suggested that the ras protein modifies the receptor-linked phosphoinositide turnover, we are currently attempting to reconstitute these ras and ras-related small Mr G proteins with the membrane phospholipase C and cell surface receptors in a cell-free system. We have also characterized the growth factor receptor-linked phosphoinositide turnover using several cell lines. In NIH/3T3 cells and cultured smooth muscle cells, the bombesin-and angiotensin II-induced phosphoinositide hydrolysis is inhibited by protein kinase C by uncoupling the G protein to the phospholipase C. In contrast, the platelet derived-growth factor-induced reaction is insensitive to protein kinase C in both cell types. These results together with our earlier observations suggest that there are various signalling pathways from the receptors to the phospholipase C.

众所周知，许多细胞外信号会引起受体连接的磷酸肌醇周转，从而诱导CA^<2+>动员和蛋白激酶C激活。从细胞表面受体到磷脂酶C的信号传导的机制尚未澄清。在该研究项目中，我们研究了GTP结合蛋白（G蛋白）在这些跨膜信号传导机制中的作用和作用。首先，我们已经纯化并表征了突触膜磷脂酶C.我们还将多个G蛋白分离出了多个G蛋白，MR值约为20.000（小MR G蛋白），包括脑，包括纯化和表征两个指定为SMG P25A和SMG P21的新型G蛋白，除了C-KKI-ras p21，以及除了C-KKI-Ras和Rho prote蛋白。有人提出，RAS蛋白会修饰受体连接的磷酸肌醇周转率，我们目前正在尝试在无细胞系统中与膜磷脂酶C和细胞表面受体重建这些RAS和RAS相关的小MR G蛋白。我们还使用多个细胞系表征了生长因子受体连接的磷酸肌醇周转。在NIH/3T3细胞和培养的平滑肌细胞中，通过将G蛋白与磷脂酶C耦合到磷脂酶C.相反，bombesin and血管紧张素II II诱导的磷酸肌醇水解受到蛋白激酶C的抑制。相反，相反，血小板衍生物衍生物衍生的生长因子诱导的生长因子诱导的对蛋白质酶Cin酶的反应不敏感。这些结果与我们先前的观察结果一起表明，从受体到磷脂酶C的各种信号通路。