インスリン刺激によるGLUT4転位には,CAPに依存するTC10の活性化が必要です
S H Chiang1, C A Baumann, M Kanzaki
1Cellular and Molecular Biology Graduate Program, University of Michigan, Ann Arbor, Michigan 48105, USA.
Nature
|April 20, 2001
まとめ
インスリンは,GLUT4トランスポーターを細胞表面に移動させることで,グルコースの吸収を刺激します. Cbl,CrkII-C3G,TC10を含む新しい経路は,PI(3) Kと連携して,この重要なプロセスを可能にします.
科学分野:
- 細胞生物学 細胞生物学
- 分子シグナル伝達です.
- メタボリック調節 メタボリック調節
背景:
- インスリン媒介によるグルコース吸収は,筋肉および脂肪組織におけるGLUT4トランスポーターの細胞表面への転位に依存しています.
- GLUT4膀の密輸は理解されているが,インスリン受容体活性化と転位を結びつける特定のシグナル伝達経路は不明である.
- フォスファディチルイノシトール-3-OHキナーゼ (PI(3) K) の活性化は,GLUT4転位には必要ですが,不十分です.
研究 の 目的:
- GLUT4転位を媒介するインスリン受容体活性化の下流のシグナル伝達経路を解明する.
- インスリン刺激によるグルコース摂取におけるCbl,CrkII-C3G複合体,TC10の役割を調査する.
- この経路がPI(3) Kシグナル伝達とどのように相互作用するかを決定する.
主な方法:
- インスリン刺激によるCblのチロシンリン酸化と,CAP経由でインスリン受容体へのCblの誘導を研究した.
- Cbl,CrkII-C3G複合体,TC10の脂質ラフトへの転移を分析した.
- Cbl,CrkII-C3G,TC10経路の活性化がグルコース吸収とGLUT4転位に与える影響を評価した.
主要な成果:
- インスリン刺激によるCblのリン酸化により,Cblが脂質ラフトに転移し,CrkII-C3G複合体を誘発する.
- CrkII-C3G複合体は,PI(3) Kとは独立して,脂質ラフト内の小さなGTP結合タンパク質TC10を活性化させます.
- TC10の活性化は,インスリン刺激によるグルコース吸収とGLUT4転位に不可欠です.
結論:
- Cbl,CrkII-C3G,TC10を含む新しいシグナル伝達経路は,インスリン刺激によるGLUT4転位に不可欠である.
- このTC10経路は,PI(3) K経路と並行して機能し,グルコース吸収に対するインスリン効果を完全に媒介する.
- この経路を理解することで,代謝調節と糖尿病の潜在的な治療目標に関する新しい洞察が得られます.
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