Hsp90-p23-GRの構造は,Hsp90クライアント再構成メカニズムを明らかにする
Chari M Noddings1, Ray Yu-Ruei Wang1, Jill L Johnson2
1Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
Nature
|December 23, 2021
まとめ
熱ショックタンパク質90 (Hsp90) とそのコチャペロンp23は,グルココルチコイド受容体 (GR) を本来のリガンド結合状態に再構成する. これはHsp90を明らかにします.
科学分野:
- 分子生物学
- 構造生物学
- 生物化学
背景:
- 熱ショックタンパク質90 (Hsp90) は,多数のクライアントタンパク質の折りたたみと活性化に不可欠な分子チャペロンです.
- グルココルチコイド受容体 (GR) は,その活動においてHsp90に大きく依存する重要なクライアントタンパク質である.
- 以前の研究では,Hsp70がGR結合を抑制し,Hsp90とp23がそれを回復させるが,分子メカニズムは不明であった.
研究 の 目的:
- GRクライアントタンパク質のHsp90媒介による再構成の分子メカニズムを解明する.
- 人間のGR-Hsp90-p23成熟複合体の冷凍電子顕微鏡 (cryo-EM) 構造を提示する.
- Hsp90とコチャペロンp23が 顧客特有の折り畳み結果を 決定する仕組みを理解する.
主な方法:
- ヒトのGR-Hsp90-p23複合体の構造を決定するための冷凍電子顕微鏡 (冷凍-EM)
- Hsp90複合体内のGRの構造を明らかにするための構造分析.
- GRの安定化とリガンド結合の強化におけるp23の役割を評価する生化学的測定法.
主要な成果:
- 凍結-EM構造は,Hsp90 ルーメン内の折りたたまれた,リガンド結合構造でGR リガンド結合領域を明らかにする.
- コチャペロンp23は,C端のヘリックス経由でネイティブGRを直接安定させ,リガンド結合を改善する.
- この構造は,以前に観察された展開されたクライアント-Hsp90複合体と対照的であり,Hsp90によるクライアント特有の折り畳み制御を強調する.
結論:
- Hsp90は,コチャペロンとクライアントの直接の相互作用により,クライアント特有の折り畳み結果を決定することができます.
- この研究は,GR再構成の分子メカニズムを詳細に説明するHsp90クライアントの最初の完全なチャペロンサイクルを提示します.
- この研究は,Hsp90機構によるクライアントタンパク質のダイナミックな調節に関する重要な洞察を提供します.
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