ラパミシン (TOR) の標的の結合パートナーであるラプターは,TORの作用を媒介する
Kenta Hara1, Yoshiko Maruki, Xiaomeng Long
1Biosignal Research Center, Kobe University, 657-8501, Kobe, Japan. harak@kobe-u.ac.jp
Cell
|August 2, 2002
まとめ
ラプターはmTORと結合し,4EBP1.1のような重要な標的をリン酸化できるようにする重要なタンパク質の支架です. この相互作用は,細胞の成長を調節し,TORシグナリングを vivo で媒介するために不可欠です.
科学分野:
- 分子生物学は分子生物学である.
- 細胞シグナリング 細胞シグナリング
- バイオケミストリー バイオケミストリー
背景:
- ラパミシン (mTOR) 経路のメカニスティックターゲットは,細胞の成長,増殖,代謝の中心的な調節因子です.
- mTORの主要な下流ターゲットは,p70 S6キナーゼアルファ (p70alpha) とエウカリオット開始因子4E結合タンパク質1 (4EBP1) を含む.
- mTOR活動の規制メカニズムの理解は,細胞ホメオスタシスと疾患状態を理解するために不可欠です.
研究 の 目的:
- mTORキナーゼ活性調節におけるmTOR結合タンパク質であるRaptorの役割を調査する.
- RaptorがmTOR信号を媒介するメカニズムを解明する.
- 細胞プロセスにおけるラプターのインビボ機能を決定する.
主な方法:
- p70alphaと4EBP1.1に対するmTOR活性を評価するためのインビトロキナーゼアッセイ.
- タンパク質とタンパク質の相互作用を研究するための共免疫プレシピテーションとプルダウンアッセイ.
- 細胞培養におけるRNA干渉 (RNAi) がラプター発現を阻害する.
- Caenorhabditis elegans (C. elegans) のRNAiは,生体内フェノタイプを研究するために研究されている.
主要な成果:
- ラプターはmTORに直接結合し,mTORで触媒化された4EBP1の効率的なリン酸化にインビトロで必要である.
- ラプター結合は,p70alpha.へ向かってmTORキナーゼの活性を増強する.
- RNAiによるラプター発現の部分的抑制は,mTOR触媒による4EBP1リン酸化を減少させる.
- C. elegansにおけるRNAi媒介によるRaptorの不活性化は,Ce-TORの不活性化時に観察されたフェノタイプを再現します.
結論:
- ラプターはmTORにとって不可欠な支架タンパク質として機能し,その基板,特に4EBP1.1のリン酸化を促進します.
- ラプターはmTOR (TOR) 信号伝達の重要な媒介者である.
- これらの発見は,細胞の成長とTOR経路の出力を制御するラプターの不可欠な役割を強調しています.
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