Role of polyphosphoinositide synthesizing enzyme in intracellar signal transduction system

多磷酸肌醇合成酶在细胞内信号转导系统中的作用

• 批准号: 60480131
• 负责人: TAKENAWA Tadaomi
• 金额: $ 3.97万
• 依托单位: Tokyo Metropolitan Institute of Gerontology (1986)The University of Tokyo (1985)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-60480131/
• 关键词: phosphatidylinositol kinase; phosphatidylinositol4; イノシトールリン脂質; 好中球

It has been well known that various hormones and autacoids enhance the inositol phospholipids metabolism, leading to various cellular responses. In this case, the degradation of phosphatidylinositol 4, 5, -bisphosphate(TPI) to diacylglycerol and inositol 1, 4, 5,-trisphosphate has been proposed to be a primary event. But, since TPI is present as a trace amount, it becomes to be depletion very rapidly. Therefore, very rapid compensatory resynthesis of TPI from phosphatidylinositol(PI) is necessary to continue the hormonal responses. This step was catalyzed by two kinases,PI kinase and phosphatidylinositol 4-phosphate(DPI) kinase.We tried to purify the enzymes and classify the characterization of them. PI kinase was purified from rat brain, by Affigel-Blue, DEAE-Biogel, Sephacryl 300, ATP-affinity and Mono Q column chromatography. Molecular weight was found to be 120,000 dalton and the specific activity increased 1250-fold, optimal pH was 7.0 and <Mg^(2+)> was required for the activity. The enzyme can only phosphorylate PI but not DPI or diacylglycerol.

众所周知，各种激素和类胡萝卜素促进肌醇磷脂的代谢，导致各种细胞反应。在这种情况下，磷脂酰肌醇4，5，二磷酸(TPI)降解成二酰甘油和1，4，5，三磷酸肌醇被认为是主要事件。但是，由于TPI以微量形式存在，它变得非常迅速地耗尽。因此，从磷脂酰肌醇(PI)非常快速地补偿重新合成TPI是必要的，以继续激素反应。这一步骤是由两种酶催化的，即磷脂酰肌醇4-磷酸(DPI)和磷脂酰肌醇(PI)激酶。通过Affigel-Blue、DEAE-Biogel、Sephacryl 300、ATP亲和层析和Mono Q柱层析，从大鼠脑中纯化了PI激酶。该酶的相对分子质量为12万道尔顿，比活力提高1250倍，最适pH为7.0，需要~lt；mg^(2+)&gt；该酶只能磷酸化PI，不能磷酸化DPI或甘油二酯。

项目成果

H. Kato, J. Ishitoya and T. Takenawa: "Inhibition of inositol phospholipids metabolism and calcium mobilization by cyclic AMP-increasing agents and phorbol ester in neutrophils." Biochem. Biophys. Res. Commun.139. 1272-1278 (1986)

H. Kato、J. Ishitoya 和 T. Takenawa：“环 AMP 增加剂和中性粒细胞中的佛波酯对肌醇磷脂代谢和钙动员的抑制。”

T. Takenawa, J. Ishitoya and Y. Nagai: "Inhibitory effect of <PGE_2> , forskolin, dibutyrylcAMP on arachidonic acid release and inositol phospholipid metabolism in guinea pig neutrophils." J. Biol. Chem.261. 1092-1098 (1986)

T. Takenawa、J. Ishitoya 和 Y. Nagai：“<PGE_2>、毛喉素、二丁酰cAMP 对豚鼠中性粒细胞花生四烯酸释放和肌醇磷脂代谢的抑制作用。”

M.Kato;Y.Homma;Y.Nagai;T.Takenawa: Biochem.Biophys.Res.Commun.129. 375-380 (1985)

M.Kato；Y.Homma；Y.Nagai；T.Takenawa：Biochem.Biophys.Res.Commun.129。

H.Kato;J.Ishitoya;T.Takenawa: Biochem.Biophys.Res.Commun.139. 1272-1278 (1986)

H.Kato；J.Ishitoya；T.Takenawa：Biochem.Biophys.Res.Commun.139。

J.Ishitoya;T.Takenawa: J.Immunol.138. 1201-1207 (1987)

J.Ishitoya；T.Takenawa：J.Immunol.138。