ヒトIFITタンパク質によるウイルス5'-PPP-RNA認識の構造的基礎
Yazan M Abbas1, Andreas Pichlmair, Maria W Górna
1Department of Biochemistry, Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Quebec H3G 0B1, Canada.
Nature
|January 22, 2013
まとめ
テトラトリコペプチドリピート (IFIT) のインターフェロン誘発タンパク質は,5'-トリフォスファート群 (PPP-RNA) のウイルスRNAを直接認識する. この構造的な洞察は,IFITが先天的な抗ウイルス防御に不可欠なウイルスRNAを区別する方法を明らかにします.
科学分野:
- 生まれながらの免疫力があります.
- 分子ウイルス学は分子ウイルス学.
- 構造生物学 構造生物学とは
背景:
- テトラトリコペプチドリピート (IFIT) によるインターフェロン誘発タンパク質は,先天的な免疫分子である.
- IFITはホストの翻訳機構を妨害することで機能すると考えられていた.
- 最近の発見は,IFITがウイルスのRNAシグネチャを直接認識することを示唆しています.
研究 の 目的:
- IFITタンパク質によるウイルスRNA認識の構造的基礎を解明する.
- IFITがウイルスRNAと宿主RNAを区別する方法を理解する.
- IFIT媒介の抗ウイルス防御のメカニズムを調査する.
主な方法:
- 人間のIFIT5およびIFIT1断片のX線結晶学.
- 5'-トリフォスファートRNA (PPP-RNA) での複合形成の研究.
- 変異分析,タンパク質分解,およびゲルシフトアッセイ.
主要な成果:
- 結晶構造はIFIT5.5で正電荷の空洞を持つ新しい螺旋領域を明らかにしました.
- この穴は,単一鎖のPPP-RNAを特に結合し,RIG-Iと区別する.
- PPP-RNA結合は配列特異性がないため,約3個の核酸の5'-オーバーハングが必要です.
- PPP-RNA結合の障害は,ヒト胚性腎臓細胞における抗ウイルス反応を損なう.
結論:
- IFITタンパク質は,専用の構造モチーフを介してウイルスのRNAを選択的に認識します.
- この認識メカニズムは,他の既知の先天性免疫センサーとは異なる.
- この発見は,IFIT媒介の抗ウイルス免疫の分子基盤についての洞察を提供します.
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