Akt依存型リン酸化による内皮細胞における酸化窒素合成酵素の活性化
S Dimmeler1, I Fleming, B Fisslthaler
1Molecular Cardiology, Department of Internal Medicine IV, University of Frankfurt, Germany.
Nature
|June 22, 1999
まとめ
Akt/PKB酵素は,内皮酸化窒素合成酶 (eNOS) を活性化し,心血管の恒常性にとって重要な酸化窒素 (NO) の生成を増加させます. この新しい経路は,eNOSのリン酸化によって媒介され,心臓血管治療のための新しい標的を提供します.
科学分野:
- 心血管生理学 心血管の生理学
- 分子生物学は分子生物学である.
- 酵素学 酵素学とは
背景:
- 内皮 NO 合成酵素 (eNOS) によって生成される内皮窒素酸化物 (NO) は,血圧の調節,血管の改造,血管新生など,心血管のホメオスタシスに不可欠です.
- 血流によって引き起こされる切断ストレスは,NO生成の主要な生理学的刺激であるが,eNOS活性化の正確なメカニズムは不明である.
- eNOSの活性がリン酸化によって調節されていることは知られていますが,関連する特定のキナーゼと経路は完全に解明されていません.
研究 の 目的:
- eNOSの活性化におけるAkt/PKB経路の役割を調査する.
- Akt/PKBがeNOSの活動を規制する特定のメカニズムを特定する.
- NO生産と心血管機能に対するこの規制メカニズムの影響を調査する.
主な方法:
- Akt/PKBとeNOSの相互作用を研究するために生化学的測定法を使用しました.
- eNOSのリン酸化部位 (セリン1177) の部位指向型変異を含む遺伝子操作が使用されました.
- フォスファディチルイノシトール-3-OHキナーゼ/アクト経路の阻害を含む様々な条件下で,NOの生成とeNOS酵素の活性を測定した.
主要な成果:
- セリン/スレオニンタンパク質キナーゼAkt/PKBがENOSの活性化を直接媒介することを示した.
- phosphatidylinositol-3-OHキナーゼ/Akt経路の阻害またはeNOS上のAktリン酸化部位 (Serine 1177) の変異は,リン酸化を弱め,eNOSの活性化を阻害することを示した.
- セルリン1177のリン酸化を模倣することで,eNOSの活性が強化され,Ca2+の感受性が変化し,生理学的レベル以下のCa2+濃度で最大限の活性化が可能になった.
結論:
- Akt/PKBによるeNOSのリン酸化は,eNOSの活動を調節するための新しい重要なメカニズムです.
- このAkt媒介のリン酸化は,eNOS活性化のためのCa2+独立経路を表しています.
- 発見は,心血管疾患の理解と治療に潜在的な影響を持つ,NO生産のための新しい規制メカニズムを明らかにします.
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