Qualitative change of GTP-binding protein.

GTP结合蛋白的质变。

• 批准号: 02670084
• 负责人: WATANABE Yasuhiro
• 金额: $ 1.41万
• 依托单位: Osaka 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: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02670084/
• 关键词: GTP-binding Protein; lithium; Protein kinase; phosphorylation; Qualitative Change; ADP-ribosylation; Pertussis Toxin; リチウム; GTP結合給白

In order to know the qualitative changes of inhibitory GTPbinding(G)protein in vitro, we did ADP-ribosylation of Gi protein by pertussis toxin(islet-activating protein, IAP), an experiment about dissociation of the trimer of the three alpha beta gamma-subunits into alpha -subunits and beta gamma -subunits and western blot using an antibody for Gi-protein. The addition with lithium ion to the protein caused a decrease of the amounts of ADPribosylation of Gi protein by IAP in human platelet membranes and weekened the inhibition'of adenylate cyclase activity by activated Gi-protein, though the dissociation of the three subunits did not change. Also, chronic treatment of manic depressive patients with lithium carbonate decreased the amounts of ADPribosylation by IAP in their platelet membranes. Next the effect of phosphorylation of partially purified Gi-protein by cyclic AMP-dependent protein kinase was studied. The treatment caused a decrease of the amounts of ADP-ribosylation of Gi protein by IAP in human platelet membranes, weekened the phospholipase C activity by activated Gi-protein in differentiated HL-60 cells and inhibited the dissociation of the three subunits induced by Mg2+ and GTPgamma S. Western blot showed no remarkable quantitative changes in Gi protein in the experimental conditions mentioned above. The results strongly suggested that the qualitative changes of Gi-proteins are physiologically and pathologically functional in the regulation of transmembrane signal transduction.

为了了解体外抑制性GTP结合(G)蛋白的质变，我们进行了百日咳毒素(胰岛激活蛋白，IAP)对Gi蛋白的ADP核糖基化，即三个αβγ三聚体解离的实验。将β-亚基分解为α-亚基和β-γ-亚基，并使用Gi​​-蛋白抗体进行蛋白质印迹。在蛋白质中添加锂离子会导致人血小板膜中IAP对Gi蛋白的ADPribosylation量减少，并减弱活化Gi蛋白对腺苷酸环化酶活性的抑制，但三个亚基的解离没有改变。此外，用碳酸锂长期治疗躁狂抑郁症患者可减少血小板膜中 IAP 引起的 ADPribosylation 的数量。接下来研究了环AMP依赖性蛋白激酶对部分纯化的Gi蛋白的磷酸化作用。该处理导致人血小板膜中 IAP 对 Gi 蛋白的 ADP-核糖基化量减少，减弱了分化的 HL-60 细胞中活化的 Gi 蛋白的磷脂酶 C 活性，并抑制了 Mg2+ 和 Mg2+ 诱导的三个亚基的解离。 GTPgamma S. Western blot显示在上述实验条件下Gi蛋白没有明显的数量变化。结果强烈表明Gi蛋白的质变在跨膜信号转导的调节中具有生理和病理功能。