Control of cell cycle checkpoint mediated by mammalian target of rapamycin

雷帕霉素哺乳动物靶标介导的细胞周期检查点的控制

基本信息

批准号：
10680609
负责人：
YONEZAWA Kazuyoshi
金额：
$ 2.11万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680609/
关键词：
amino acid leucine mitogen rapamycin mTOR protein synthesis p70 S6 kinase eIF4E binding protein インスリン mTORキナーゼ細胞増殖 eIF-4E BP-1

项目摘要

Rapamycin is a lipophilic macrolide compound and binds to FKBP12 in mammalian cells. The mTOR (mammalian target of rapamycin) protein was identified as a target of FKBP12-rapamycin complex. This protein has a calculated molecular weight of 289 kDa and contains a kinase-like domain at its carboxyl-terminus. In this study, we obtained following findings.(1)mTOR participates in nutrient-sensing, especially amino acid-sensing, in mammalian cells and regulates translational effectors, such as p70S6 kinase α (p70α) and eIF4E binding protein (4EBP).(2)Activation of amino acid-mTOR signaling pathway is indispensable for mitogen-induced protein synthesis. In other words, amino acid-mTOR signaling is a priming signal for mitogen-induced protein synthesis.(3)Among amino acids, leucine has the most potent ability to activate phosphorylation of p70α.(4)p70α, extracted in inactive forms from rapamycin-treated cells, can be directly phosphorylated by the mTOR kinase at the rapamycin-sensitive site Thr-412. mTOR-catalyzed p70α phosphorylation in vitro is accompanied by a substantial restoration in p70α kinase activity.(5)Sequential phosphorylation of p70α by mTOR and 3-phosphoinositide-dependent protein kinase 1 in vitro results in a synergistic stimulation of p70α activity to levels similar to that attained by serum stimulation in vivo.(6)Several candidates of binding partners of mTOR were identified using conventional biochemical methods and yeast-two hybrid system and detailed analyses are now in progress.(7)Some of leucine derivatives were found to have the ability to inhibit p70α activation and T cell proliferation. This analysis is also now in progress.

雷帕霉素是一种亲脂性大环内酯化合物，可与哺乳动物细胞中的 FKBP12 结合。 mTOR（雷帕霉素的哺乳动物靶标）蛋白被确定为 FKBP12-雷帕霉素复合物的靶标，该蛋白的计算分子量为 289 kDa，并含有激酶样物质。在本研究中，我们得到了以下发现：(1)mTOR参与营养感应，特别是氨基。哺乳动物细胞中的酸感应并调节翻译效应子，例如p70S6激酶α（p70α）和eIF4E结合蛋白（4EBP）。（2）氨基酸-mTOR信号通路的激活对于丝裂原诱导的蛋白质合成是必不可少的。换句话说，氨基酸-mTOR信号是丝裂原诱导的蛋白质合成的启动信号。(3)氨基酸中，亮氨酸具有最强的激活能力。 p70α 的磷酸化。(4)p70α 以非活性形式从雷帕霉素处理的细胞中提取，可在雷帕霉素敏感位点 Thr-412 处被 mTOR 激酶直接磷酸化，mTOR 催化的 p70α 磷酸化在体外会显着恢复。 (5)mTOR 和 3-磷酸肌醇依赖性的 p70α 顺序磷酸化体外蛋白激酶1导致p70α活性协同刺激，达到与体内血清刺激所达到的水平相似的水平。(6)使用常规生化方法和酵母-二杂合系统和详细分析鉴定了mTOR结合配偶体的几个候选者(7)一些亮氨酸衍生物被发现具有抑制p70α激活和T细胞增殖的能力。该分析也正在进行中。