バクテリアのIII型エフェクターファミリーのフォスフォトレオニンライゼ活性
1National Institute of Biological Sciences, Beijing, 102206, China.
まとめ
シゲッラ菌は,III型分泌システムを使用して,ミトゲン活性化タンパク質キナーゼ (MAPK) を,リン酸塩基を除去することによって無活性化するタンパク質 OspF を注入します. このフォスフォトレオニンライゼの活動により,宿主細胞の信号伝達が妨げられます.
科学分野:
- 微生物学 微生物学とは
- 細胞生物学 細胞生物学
- バイオケミストリー バイオケミストリー
背景:
- 病原性細菌は,第3型分泌システム (T3SS) を用いて,受容体細胞にエフェクタータンパク質を注入する.
- これらのエフェクターは,宿主細胞の信号伝達経路を操作して,感染を促進します.
- ミトゲン活性化タンパク質キナーゼ (MAPK) は,細菌の病原体によってしばしば標的にされる重要なシグナル伝達分子です.
研究 の 目的:
- シーゲラ型IIIエフェクターOspFがミトゲン活性化タンパク質キナーゼ (MAPK) を無効化するメカニズムを調査する.
- OspF媒介によるMAPK不活性化に起因する酵素活性を特徴づける.
主な方法:
- MAPKに対するOspFの酵素活性を評価するためのインビトロアッセイ.
- OspF治療後のMAPKの改変を分析するための質量スペクトロメトリ.
- OspFの活性と他の関連するエフェクタータンパク質の比較.
主要な成果:
- Shigella OspFは,細胞外信号調節キナーゼ1と2 (Erk1/2),c-Jun N-ターミナルキナーゼ,p38.8を含むMAPKを不可逆的に不活性化する.
- OspFは,MAPKの活性化ループのフォスフォトレオニン残基から特にリン酸群を除去します.
- 質量スペクトロメトリーはp-Erk2の98ダルトンの質量損失を確認し,これはフォスフォストリオニンの分裂を示唆しています.
- この新しい酵素活性は,フォスフォトレオニンリアゼと呼ばれ,OspFファミリーメンバーの間で保存されていることが判明しました.
結論:
- OspFは,MAPKを標的としたフォスフォトレオニンライゼとして機能し,不活性化させます.
- この酵素活性は,宿主信号伝達経路の細菌操作のための新しいメカニズムを表しています.
- MAPKの特異性は,宿主防御を覆すためのシゲラによるターゲットを絞った戦略を示唆しています.
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