Gタンパク質との複合体における活性化されたGLP-1受容体の冷凍-EM構造
Yan Zhang1, Bingfa Sun2, Dan Feng2
1Life Sciences Institute and Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA.
Nature
|May 25, 2017
まとめ
グルカゴン型ペプチド1 (GLP-1) は,細胞外ループと膜内核によって形成されたポケットに結合することによって,その受容体 (GLP-1R) を活性化します. この構造的洞察は,GLP-1R-Gs複合体の形成を明らかにし,B級GPCR活性化の理解を進める.
科学分野:
- 構造生物学
- 生物化学
- 分子薬理学
背景:
- グルカゴン様ペプチド1 (GLP-1) は,グルコースの恒常性と食欲を調節する重要なホルモンです.
- GLP-1は,クラスBのGタンパク質結合受容体 (GPCR) であるGLP-1受容体 (GLP-1R) を活性化することで効果を発揮する.
- クラスBのGPCR活性化メカニズムの理解は不可欠ですが,活性化された全長受容体に関する構造データがないため制限されています.
研究 の 目的:
- ペプチド活性化GLP-1受容体G複合体の近原子解像度の冷凍電子顕微鏡構造を決定する.
- ペプチドホルモンによるクラスBのGPCR活性化の構造的基礎を解明する.
主な方法:
- GLP- 1R- G複合体を視覚化するために,冷凍電子顕微鏡 (cryo- EM) が使用された.
- 複合体では原子に近い解像度で構造分析が行われました.
主要な成果:
- 構造は,ペプチドホルモンが受容体のN端領域,トランスメブランコア,細胞外ループによって形成された結合ポケットの中に保持されていることを明らかにする.
- ホルモン結合は,トランスメブラン領域の構造変化,特にトランスメブランヘリックス6の歪みを誘発する.
- この形状の変化は,Gsタンパク質のアルファ5ヘリックスに対応するヘリックス6の細胞内半分の外向きの回転を容易にする.
結論:
- この研究は,ペプチドホルモン結合時のクラスBのGPCRの活性化メカニズムを理解するための最初の構造的枠組みを提供します.
- この構造的洞察は,GLP-1Rおよび関連する受容体を標的とした治療法の合理的な設計に不可欠です.
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