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タンパク質品質管理におけるリボソーム関連E3ユビキチンリガゼの役割
Mario H Bengtson1, Claudio A P Joazeiro
1Department of Cell Biology, The Scripps Research Institute, CB168, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Nature
|September 14, 2010
まとめ
ユカリオット細胞は,Ltn1ユビキチンリガゼを使用して異常タンパク質を除去し,これはノンストップメッセンジャーRNA (mRNA) 製品を分解するために標的とします. この発見は,酵母における重要なタンパク質品質管理経路を明らかにし,神経変性疾患への影響を及ぼしています.
科学分野:
- 分子生物学は分子生物学である.
- 細胞生物学 細胞生物学
- バイオケミストリー バイオケミストリー
背景:
- ノンストップメッセンジャーRNA (mRNA) にストップコドンが欠けることは,遺伝子発現の誤りから生じ,潜在的に有害な異常タンパク質に繋がる可能性があります.
- 細菌は,これらのノンストップタンパク質の共同翻訳タグ付けと分解のためにtmRNA (トランスファーメッセンジャーRNA) を利用します.
- ユカリオットのノンストップタンパク質除去のメカニズムは,ほとんど未知のままでした.
研究 の 目的:
- ユカリオット細胞がノンストップタンパク質を識別し,除去するメカニズムを解明する.
- この細胞過程におけるLtn1 E3ユビキチンリガゼの役割を調査する.
主な方法:
- リングドメイン型E3ユビキチンリガゼであるSaccharomyces cerevisiae Ltn1の機能を調査した.
- Ltn1とリボソームの関連性を調べました.
- 新生ノンストップタンパク質の普遍化とその後のタンパク質分解を分析した.
主要な成果:
- Ltn1は主にリボソームとユビキチナート新生ノンストップタンパク質と関連しています.
- このユビキティレーションは,ノンストップタンパク質のプロテアソマル分解をシグナルする.
- Ltn1媒介のユビキティレーションは,リボソームが複合体 (A) 尾の翻訳中に停止することによって引き起こされます.
- Ltn1機能の喪失は,絶え間ないタンパク質の蓄積によるストレスに対する感受性を高めます.
結論:
- Ltn1は,バクテリアのtmRNAに類似して,真核生物のノンストップタンパク質品質管理の重要な構成要素として機能します.
- この経路は,タンパク質体分解のためのリボソーム結合と無限度を含む.
- 欠陥のあるLtn1機能は,リストリン変異のマウスで観察された神経変性現象に寄与する可能性があります.
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