E1およびE2酵素から独立してバクテリアエフェクターによるユビキチン化
Jiazhang Qiu1, Michael J Sheedlo2, Kaiwen Yu3
1Purdue Institute for Inflammation, Immunology and Infectious Disease and Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907, USA.
Nature
|April 7, 2016
まとめ
Legionella pneumophilaのような細菌の病原体は新しい酵素を用いて宿主タンパク質を ubiquitinateする. このプロセスは従来のE1/E2酵素を回避し,ユビキチン活性化にはニコチナミドアデニンジヌクレオチドのみが必要です.
科学分野:
- 細胞生物学
- 微生物学
- 生物化学
背景:
- ユビキチネーションは,真核細胞のプロセスを調節する重要な翻訳後の修正である.
- 定規のユビキチネーション経路には,E1,E2,E3という3つの酵素のカスケードが含まれています.
- 伝染剤はしばしば生存と複製のためにユビキチネーションネットワークを標的とする.
研究 の 目的:
- レジオネラ・プネモフィラエフェクタが宿主標的を ユビキチナートするメカニズムを調べる
- 細菌のユビキチン化活動には宿主のE1およびE2酵素が必要かどうかを判断する.
- バクテリアのエフェクタ媒介のユビキチン化における特定のモチーフの役割を解明する.
主な方法:
- レジオネラ・プネモフィラのSIDE家族エフェクタの識別と特徴付け
- 細菌エフェクター,ユビキチン,および様々な基板 (例えば,Rab GTPases) を用いたin vitroユビキチネーションアッセイ
- 酵素活性測定は,E1,E2酵素,ATP,およびニコチナミドアデニン・ディヌクレオチド (NAD) の必要性を評価する.
- SidEエフェクター内の疑似モノ-ADP-リボシルトランスフェラーゼモチブの変異分析.
- 細胞内複製アッセイは,原生体の宿主において,SIDEエフェクターのインビボ機能を評価する.
主要な成果:
- レジオネラ・プネモフィラ SidEファミリーのエフェクタは,宿主Rabの小さなGTPasesをユビキチナートする.
- これらのバクテリアエフェクターは宿主E1およびE2酵素から独立してユビキチン化を触媒化する.
- 保存されたモノ-ADP-リボシルトランスフェラーゼモチブは,SIDEエフェクタのユビキチン化活動に不可欠である.
- E1/E2独立のユビキチン化反応は,ニコチナミドアデニン・ディヌクレオチド (NAD) によって推進され,ADPリボシレートされたユビキチンを形成する.
- SidEのユビキチネーション活動は,原生体の細胞内細菌複製に不可欠である.
結論:
- ユビキチネーションは,定規のE1/E2カスケードとは独立した単一の酵素によって触媒化される.
- レギオネラ・プネモフィラは,宿主細胞の操作のために新しいE1/E2独立のユビキチネーションメカニズムを使用します.
- このバクテリアの戦略は,ユビキチネーション経路の適応性と病原体による利用を強調しています.
- 発見は,宿主-病原体相互作用と基本的なユビキチネーション生物学の両方を理解するための潜在的意味を持つ新しいユビキチン改変のモードを明らかにします.
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