グルカゴン受容体のRAMP2による負アロステリック調節
Kaavya Krishna Kumar1, Evan S O'Brien1, Chris H Habrian1
1Department of Molecular and Cellular Physiology, Stanford University School of Medicine, 279 Campus Drive, Stanford, CA 94305, USA.
Cell
|March 31, 2023
まとめ
受容体活性調節タンパク質2 (RAMP2) は,受容体の柔軟性を高めることで,グルカゴン受容体 (GCGR) のシグナル伝達を阻害する. この相互作用は GCGR を破壊する.
科学分野:
- 生物化学
- 分子生物学
- 構造生物学
背景:
- 受容体活性調節タンパク質 (RAMPs) は,B族のGタンパク質結合受容体 (GPCRs) の主要な調節剤である.
- グルカゴン受容体 (GCGR) は,血糖の恒常性を維持する上で重要な役割を果たします.
研究 の 目的:
- RAMP2とGCGRの相互作用を調査する.
- RAMP2がGCGR活動を調節するメカニズムを解明する.
主な方法:
- 水素-デュテリウム交換質量スペクトロメトリ (HDX-MS)
- 体細胞表面の光共振エネルギー伝送 (smFRET)
- 電子冷凍顕微鏡 (EM冷凍)
主要な成果:
- RAMP2はGCGRと直接相互作用し,下流の信号伝達を幅広く抑制する.
- RAMP2は,GCGR細胞外領域 (ECD) とトランスメブランヘリックス6における局所的な柔軟性を高めます.
- CRYO-EMでは,RAMP2に結合したGCGRと,乱れたECDと,細胞内活性化の特徴が再配置されていることが判明した.
結論:
- RAMP2はGCGRの負アロステリック変調剤として作用する.
- RAMP2は,細胞外ドメインのコンフォーメーションサンプリングを促進することで,GCGRを阻害し,シグナル伝達を減少させます.
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