Sirtuin 4は,リポアミダースを調節するピルバート脱水素酶複合体の活性である
Rommel A Mathias1, Todd M Greco2, Adam Oberstein2
1Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA; Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Australia.
Cell
|December 20, 2014
まとめ
SIRT4は脱酸化酵素ではなくリポアミダゼであり,リポアミド共因子を除去することによって,ピルバ酸脱酸化酵素複合体 (PDH) を調節する. この発見は,SIRT4を明らかにしています.
科学分野:
- バイオケミストリー バイオケミストリー
- 分子生物学は分子生物学である.
- メタボリック・レギュレーション
背景:
- Sirtuins (SIRTs) はNAD+に依存する酵素で,老化と代謝を含む様々な細胞プロセスに関与する.
- ミトコンドリアシルトゥインSIRT4とSIRT5は,制限されたデセチラゼ活性を示し,SIRT4の触媒機能はほとんど特徴づけられていない.
- ピルバート脱水素酶複合体 (PDH) は,ピルバートのアセチル-CoAへの変換を調節する重要な代謝酵素複合体です.
研究 の 目的:
- ミトコンドリアのSirtuin 4 (SIRT4) の触媒的活動と機能を明らかにする.
- ピルバ酸脱水素酶複合体 (PDH) の調節におけるSIRT4の役割を調査する.
- 代謝障害の潜在的な治療標的としてSIRT4を特徴付ける.
主な方法:
- リポイルライシンとアセチルライシンを含む様々な基板におけるSIRT4の触媒活性を決定するための酵素分析.
- PDH複合体の成分,特にダイヒドロリポイリサインアセチルトランスフェラーゼ (DLAT) の生化学分析.
- ネズミの肝臓における細胞およびin vivo研究で,SIRT4がPDH活性とリポイル化に及ぼす生理学的影響を評価する.
主要な成果:
- SIRT4はリポアミダゼとして機能し,リポアミドコファクターをライシン残基から効率的に水解する.
- SIRT4のリポアミダゼ活性度は,そのデアセチラゼ活性よりも著しく高い.
- SIRT4はPDH複合体の成分であるDLATを直接標的にし,PDHの活性低下につながります.
- 細胞モデルとマウスの肝臓で,SIRT4媒介によるPDH活性抑制が観察されました.
- グルタミン誘発の代謝流は,SIRT4のリポアミダース機能を活性化し,PDHを阻害する.
結論:
- SIRT4はミトコンドリアのリポアミダゼで,リポアミドコファクターをDLATから分離することでPDHの活性を調節する.
- このリポアミダゼ活性がSIRT4の主な触媒的機能であり,その既知の脱セチラゼ機能とは異なる.
- SIRT4は,細胞代謝の重要な調節体として作用し,特にグルタミン刺激のような代謝シグナルに反応する.
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