ERタンパク質ターゲティング中のリボソームのNACからSRPへの信号配列移転のメカニズム
Ahmad Jomaa1, Martin Gamerdinger2, Hao-Hsuan Hsieh3
1Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, 8093 Zurich, Switzerland.
まとめ
ポリペプチド関連複合体 (NAC) は,新生ポリペプチドと相互作用することによって,タンパク質標的を調節する. NACは,シグナル認識粒子 (SRP) アクセスを管理するために2つのドメインを使用し,誤ったターゲティングを防ぐために正しいタンパク質の局所化を保証します.
科学分野:
- 分子生物学
- 細胞生物学
- タンパク質の密輸
背景:
- 新生ポリペプチド関連複合体 (NAC) は,リボソームから出る新合成タンパク質に結合する.
- NACはシグナル認識粒子 (SRP) と競合し,タンパク質が内 плазма網膜 (ER) に誤って標的化されるのを防ぐ.
- NAC-SRP対抗と信号媒介SRPの関与のメカニズムは不明である.
研究 の 目的:
- NACがSRPにどのように敵対するのかを明らかにする.
- ERターゲティング信号がNAC媒介によるSRP阻害を克服する方法を理解する.
- 新興チェーンへの SRP アクセスを制御する NAC ドメインの役割を定義する.
主な方法:
- タンパク質とリボソームの相互作用を研究する生化学分析
- 新興チェーン・バインディングとSRP競争の分析
- NAC領域の構造的動態を調査する.
主要な成果:
- NACは,SRPの結合を制御するために,相反する機能を持つ2つのドメインを使用します.
- 核球領域は,信号のないリボソームでSRPを阻害する.
- 柔軟なドメインは一時的にSRPを結合し,新生チェーンスキャンを可能にします.
- ER信号は NACの球体領域を不安定化し, SRPへのアクセスを容易にする.
結論:
- NACは,新生ポリペプチドへのSRPアクセスを制御するゲートキーパーとして機能します.
- デュアルドメインメカニズムは,早めのERターゲティングを防ぐことによって,正確なタンパク質の局所化を保証します.
- ER信号の出現は,NACのSRPの解放を誘発し,効率的なターゲティングを可能にします.
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