ATPase TRIP13による細胞サイクルチェックポイントタンパク質MAD2の再構築のメカニズム
Claudio Alfieri1, Leifu Chang1,2, David Barford3
1MRC Laboratory of Molecular Biology, Cambridge, UK.
Nature
|July 6, 2018
まとめ
スピンドル・アセンブリ・チェックポイントは 細胞分裂を制御することで ゲノムの安定性を確保します この研究は,TRIP13とp31がミトスのチェックポイント複合体を分解し,適切な染色体分離のためのチェックポイントを無効化する方法を明らかにしています.
科学分野:
- 分子生物学
- 細胞生物学
- 構造生物学
背景:
- ミトーシス中のゲノム安定性は,スパインドルアセンブリチェックポイント (SAC) によって制御される.
- ミトスチェックポイント複合体 (MCC) は,アナフェーズ促進複合体 (APC/C) を阻害するSACの重要なエフェクターである.
- アクティブMCCアセンブリは,MAD2の形状の変化を含む,結合していないキネトコアによって誘発される.
研究 の 目的:
- TRIP13とp31がMCCを分解するメカニズムを解明する.
- AAA+ ATPase TRIP13が,閉じたMAD2 (C-MAD2) コンフォマーを,不活性な開いたMAD2 (O-MAD2) 形態にどのように再構成するかを理解する.
主な方法:
- TRIP13-p31彗星-C-MAD2-CDC20複合体の冷凍電子顕微鏡 (Cryo-EM) が使用されている.
- MCCの分解のダイナミクスを理解するための分子モデリング
主要な成果:
- Cryo-EM構造は,p31彗星がC-MAD2をTRIP13ヘクサマーに採用し,MAD2のN端 (MAD2NT) をTRIP13の軸毛穴に挿入するために位置づけています.
- TRIP13は,MAD2NTに沿ったATP依存型トランスロケーションを使用して,C-MAD2-p31彗星複合体を歪め,αAヘリクスを解き放ち,C-MAD2を不安定化する.
- このプロセスは,O-MAD2の形成と,MAD2のp31彗星からの解離を促進し,MCCの解体につながります.
結論:
- この研究は,TRIP13-p31彗星複合体によるMCC分解の詳細なメカニズムを示しています.
- これは,p31cometのようなアダプタータンパク質がAAA+ATPアゼに基板を勧誘する方法を強調しています.
- AAA+ ATPaseの軸性毛穴経由での転位がタンパク質の再構成をどのように誘導するかについてのモデルが提案されています.
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