結晶構造とタンパク質キナーゼC βIIIIのアロステリック活性化
Thomas A Leonard1, Bartosz Różycki, Layla F Saidi
1Laboratory of Molecular Biology, National Institutes of Health, Bethesda, MD 20892, USA.
Cell
|January 11, 2011
まとめ
タンパク質キナーゼC (PKC) イゾ酵素は,重要な脂質シグナル伝達効果因子である. 構造研究は,PKCβII活性化のための新しい2段階のアロステル調節機構を明らかにし,C1Bドメインの相互作用と膜結合を含む.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- 構造生物学 構造生物学とは
背景:
- タンパク質キナーゼC (PKC) イゾ酵素は,脂質シグナル伝達経路を媒介する.
- PKCは,ダイアシルグリセロールがC1ドメインに結合することで活性化され,膜転位を引き起こします.
- PKCイソ酵素のアロステリック調節を理解することは,細胞シグナル伝達を解読する上で極めて重要です.
研究 の 目的:
- タンパク質キナーゼCβII (PKCβII) の活性化の構造的基礎を解明する.
- PKCβII.のアロステリック活性化経路における中間形状を明らかにする.
- タンパク質キナーゼ機能における新しい規制メカニズムを特定する.
主な方法:
- 4.0 Åの解像度のX線結晶学で,全長PKCβII.IIの構造を決定する.
- 閉じた形状の低解像度溶液構造を導出するための小角X線散射 (SAXS).
- タンパク質の構造を分析し,アロステル調節を理解する.
主要な成果:
- 結晶構造は,PKCβII.の予期せぬ中間形状を明らかにした.
- キナーゼ活性部位はアクセス可能ですが,NFDモチーフにおけるPhe629のシフトにより,低活性状態です.
- C1Bドメインは低活性コンフォームを安定させることが判明し,これは膜結合時に逆転する.
結論:
- PKCβIIの活性化には2段階のアロステル調節プロセスが含まれています.
- 膜結合は,NFDヘリックス上のC1Bドメインの抑制クランプを逆転させます.
- 新しいタンパク質キナーゼの規制メカニズムが特定されました.
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