14-3-3タンパク質は,ハイブリッドプレニル-リン酸化モチーフと相互作用して,Gタンパク質を阻害する
Philippe Riou1, Svend Kjær, Ritu Garg
1Randall Division of Cell and Molecular Biophysics, New Hunt's House, King's College London, London, UK.
Cell
|April 30, 2013
まとめ
14-3-3タンパク質は,独特のC端末部位経由で,構成的に活性なGタンパク質であるRnd3と結合する. ファーネシレーションとリン酸化を含むこの相互作用は,Rnd3の活性を阻害し,それをサイトゾールに移動させます.
科学分野:
- 分子生物学は分子生物学である.
- 細胞シグナル伝達 細胞信号伝達
- タンパク質生化学 タンパク質生化学
背景:
- Gタンパク質のシグナリングは,通常,GTP/GDP結合状態のスイッチングに依存します.
- Rho GTPasesはしばしばRhoGDIによって調節される.
- Rndタンパク質は非典型的であり,構成的にGTPに結合したRhoタンパク質であり,規則は不明である.
研究 の 目的:
- Rndタンパク質,特にRnd3.3の規制メカニズムを解明する.
- Rnd3.3の拘束力のあるパートナーとインタラクションサイトを特定する.
- Rnd3規制の機能的な影響を理解するために.
主な方法:
- 14-3-3結合部位を特定するためのサイト指向型変異およびペプチド合成.
- プロテインキナーゼ (ROCK) とプロテインキナーゼC (PKC) を含有するRho関連クロールコイルを用いた酸化アッセイ.
- 14-3-3に結合したRnd3ペプチドの結晶構造の決定.
- Rnd3転位を評価するための細胞局所化研究.
主要な成果:
- Rnd3 C末端に14-3-3結合部位が特定され,FarnesylationとROCK依存型リン酸化 (Ser240) の両方を必要としている.
- 追加のリン酸化部位 (ROCKによるSer218および/またはPKCによるSer210) はさらに14-3-3結合を媒介する.
- 結晶構造は,14-3-3タンパク質を明らかにし,ファルネシル群を水嫌性溝に収納した.
- 14-3-3結合は,Rnd3誘発の細胞丸化を阻害し,プラズマ膜からサイトゾールへの転位を引き起こします.
- 同様の相互作用がRnd1,Rnd2,およびゲラニルゲラニル化ラップ1Aに観察されました.
結論:
- Rndタンパク質は,C端末の改変とリン酸化を含む新しいメカニズムを通じて14-3-3タンパク質によって調節されます.
- この相互作用は,従来のGTP/GDPスイッチとは異なる,前例のないGタンパク質阻害モードを提供します.
- この発見は,Rho GTPasesとRasスーパーファミリーの新しいレギュレーション層を明らかにしています.
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