"Research of crosstalk between nutrient sensing mTOR signaling pathway and energy metabolic sensing AMPK"

“营养传感mTOR信号通路与能量代谢传感AMPK之间的串扰研究”

基本信息

批准号：
15590273
负责人：
TOKUNAGA Chiharu
金额：
$ 2.43万
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：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15590273/
关键词：
mTOR AMPK nutrient sensor energy metabolic sensor p70 S6 kinase 4EBP1 raptor TOS motif rapamycin リン酸化 Kog1

项目摘要

1.The inhibition of mTOR signaling pathway by AMPKWe isolated a portion of the γ1 subunit of AMPK, which played a role as an energy metabolic sensor, by yeast two-hybrid screening using mTOR kinase domain as a bait. This result suggests the possibility of the linkage between the nutrient sensing mTOR signaling pathway and the cellular energy metabolic system. Actually the treatments of mammalian cells with AMPK activators inhibit phosphorylations of p70 S6 kinase (p70 S6k) and eukaryotic translational initiation factor 4E binding protein (4EBP1) which function as downstream effectors of mTOR, however a rapamycin-resistant p70 S6k variant is insensitive to AMPK activators. In addition, overexpression of the constitutively active form of AMPK in mammalian cells inhibits phosphorylations of both p70 S6k and 4EBP1. On the other hand, in the dominant negative form of AMPK-over-expressing cells, these inhibitions are restored. These results suggest a possible linkage between AMPK and mTOR signaling.2.The analysis of a role of mTOR interacting protein raptor as a scaffold proteinBoth p70 S6k and 4EBP1 have evolutionally conserved TOS (TOR signaling) motif. The mutants of this motif are no longer pbosphorylated by mitogens in cells. We showed that the TOS motif was a binding site of mTOR binding protein raptor. The mutants of the TOS motif cannot bind to raptor and these mutants can be no longer phosphorylated by mTOR in the presence of both mTOR and raptor.

1.AMPK对mTOR信号通路的抑制我们以mTOR激酶结构域为诱饵，通过酵母双杂交筛选，分离出了AMPK的一部分γ1亚基，其起到能量代谢传感器的作用。这一结果表明了这种可能性。营养感应 mTOR 信号通路与细胞能量代谢系统之间的联系实际上，用 AMPK 激活剂处理哺乳动物细胞会抑制 p70 S6 激酶 (p70 S6k) 的磷酸化和真核翻译起始因子 4E 结合蛋白 (4EBP1) 作为 mTOR 的下游效应子，但雷帕霉素抗性 p70 S6k 变体对 AMPK 激活剂不敏感。此外，哺乳动物细胞中 AMPK 组成型活性形式的过度表达会抑制两者的磷酸化。另一方面，在 AMPK 过表达细胞的显性阴性形式中，这些这些结果表明AMPK和mTOR信号传导之间可能存在联系。2.mTOR相互作用蛋白raptor作为支架蛋白的作用分析p70 S6k和4EBP1都具有进化上保守的TOS(TOR信号传导)基序。我们发现 TOS 基序是 mTOR 结合蛋白 raptor 的结合位点。 TOS 基序的突变体不能与 mTOR 结合。在 mTOR 和 raptor 存在的情况下，raptor 和这些突变体不再被 mTOR 磷酸化。