核分裂体によるcGASの抑制の構造的基礎
Tomoya Kujirai1, Christian Zierhut2, Yoshimasa Takizawa1
1Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
Science (New York, N.Y.)
|September 11, 2020
まとめ
サイクルグアノシン・モノフォスファート・アデノシン・モノフォスファート合成酵素 (cGAS) は核細胞によって抑制され,自己免疫反応を防ぐ. 構造分析により,cGASが核分裂体と結合し,活性化部位と二分化部位を阻害する.
科学分野:
- 分子生物学
- 免疫学
- 構造生物学
背景:
- 循環グアノシン・モノフォスファート・アデノシン・モノフォスファート合成酵素 (cGAS) は,炎症反応を誘発する病原性DNAの重要なセンサーである.
- ホストDNAの核細胞組織がcGASの自己活性化を制限するメカニズムは以前は知られていなかった.
- cGASの調節を理解することは,異常な免疫信号の制御に不可欠です.
研究 の 目的:
- 核素媒介によるcGAS抑制の構造的基礎を解明する.
- クロマチンの構造が自己DNAがcGASを活性化するのを防ぐことを理解する.
主な方法:
- クリオ電子顕微鏡 (cryo-EM) を用いて,ヒトのcGAS-核素子核粒子 (NCP) 複合体の構造を決定した.
- 構造的発見を検証するために,部位指向型変異を含む生化学的測定を行った.
主要な成果:
- 凍結EM構造は,2つのcGASモノマーが2つのNCPを橋渡しし,ヒストンH2A-H2B酸性パッチとヌクレオソームDNAと相互作用することを明らかにします.
- この相互作用は,cGASのDNA結合部位を隔離し,cGASの二分化を阻害し,どちらもその活性化に不可欠である.
- cGASと酸性パッチの相互作用を妨げる突然変異は,核細胞阻害を緩和する.
結論:
- DNAの核体組織は,自己DNAのcGAS活動を静止させる構造的メカニズムを提供します.
- この研究は,クロマチンがcGAS媒介の自己免疫反応をどのように防ぐかを説明する構造的枠組みを提供します.
- この発見は先天的な免疫感知経路の 調節に関する洞察を与えてくれます
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