フォスフォリファーゼC-β1は,Gq/11のGTPアゼ活性化タンパク質であり,その生理学的調節因子である
G Berstein1, J L Blank, D Y Jhon
1Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas 75235-9041.
Cell
|August 7, 1992
まとめ
フォスフォリファーゼC-β1 (PLC-β1) は,Gq/11のGTP酶活性化タンパク質 (GAP) として作用し,GTPの水解を加速する. この発見は,生理学的条件下でGタンパク質のシグナル伝達がどのように急速に無効化するかを説明します.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- 細胞シグナル伝達 細胞信号伝達
背景:
- Gq/11は,信号伝導に不可欠なヘトロトリメリックGタンパク質です.
- Gタンパク質によるGTPの水解は,信号終了の重要なステップです.
- Gタンパク質シグナル伝達がin vivoで急速に無効化するメカニズムは,まだ完全に理解されていません.
研究 の 目的:
- Gq/11活動の調節におけるフォスフォリファーズC-β1 (PLC-β1) の役割を調査する.
- PLC-β1がGq/11.1.のGTPアゼ活性を直接調節できるかどうかを判断する.
- Gタンパク質のシグナル伝達非活性化に対するPLC-β1の機能の影響を調査する.
主な方法:
- 精製されたM1マスカリン塩素受容体とGq/11を脂質小胞で再構成する.
- PLC-β1の存在と欠如におけるGq/11のGTPアゼ活性測定 1.
- GTP-GDPの交換率とGTPの水解率の測定.
主要な成果:
- 浄化されたPLC-β1は,Gq/11の基礎GTPアゼ活性を20倍まで有意に刺激した.
- この刺激は,受容体媒介のGTP-GDP交換に依存していた.
- PLC-β1は,Gq/11に結合したGTPの水解を50倍以上加速した.
- PLC-β1のGTPase活性化タンパク質 (GAP) の活動は,Gq/11.11に特異的であった.
結論:
- PLC-β1は,Gq/11.1.の生理学的GTPase活性化タンパク質 (GAP) として機能する.
- PLC-β1のこのGAP活動は,Gタンパク質媒介の信号伝達の迅速な無効化のためのメカニズムを提供します.
- この発見は,Gタンパク質の遅い内在のGTPase活性と,細胞信号伝達経路におけるその急速な回転を調和させています.
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