メタボトロプ的グルタミン酸受容体によるGタンパク質活性化
Alpay B Seven1, Ximena Barros-Álvarez1, Marine de Lapeyrière2
1Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
Nature
|July 1, 2021
まとめ
C族のGタンパク質結合受容体 (GPCRs) はジマーとして機能する. この研究は,メタボトロピクグルタミン酸受容体2 (mGlu2) の活性化が,新しいメカニズムを通じてGタンパク質結合を可能にするために,トランスメブランドメインを再配置することを明らかにしています.
科学分野:
- 生物化学
- 構造生物学
- 分子薬理学
背景:
- C族のGタンパク質結合受容体 (GPCRs) は,信号伝達に不可欠な義務ダイマーである.
- 細胞外ドメインへのリガンド結合は,よく理解されていないメカニズムを通じて,トランスメブラン (TM) ドメイン経由でGタンパク質の活性化を誘発する.
研究 の 目的:
- C族のGPCRによるGタンパク質活性化の構造的メカニズムを解明する.
- Giタンパク質との複合体におけるメタボトロピクグルタミン酸受容体2 (mGlu2) ホモディマーの構造を決定する.
主な方法:
- 高解像度構造を得るためのX線結晶学.
- 異なる機能状態のmGlu2ホモダイマーの分析
- mGlu2-Gi複合体の構造的特徴
主要な成果:
- 構造は,細胞外活性化時にTMドメインの広範な再配置を明らかにし,非対称なTM6-TM6インターフェースを形成します.
- 非活性mGlu2へのGi結合が観察されているが,ヌクレオチドフリートランジションには活性状態のTM6-TM6インターフェースが必要である.
- Gタンパク質結合は,他のGPCRファミリーで見られるTM6の開口とは異なる細胞内ループ2と3とC端を含む.
結論:
- C族のGPCRによるGタンパク質活性化のための新しいメカニズムが提案され,グローバルとローカルな構成の変化が含まれています.
- この発見は,mGlu2および関連する受容体のアロステリックシグナル伝達に関する洞察を提供します.
- この研究は,GPCRの活性化パラダイムの理解を広げています.
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