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ロカグラートはDEAD-boxタンパク質 eIF4Aをシーケンスを選択するトランスレーション抑制剤に変換する
Shintaro Iwasaki1, Stephen N Floor1, Nicholas T Ingolia1
1Department of Molecular and Cell Biology, Center for RNA Systems Biology, University of California, Berkeley, California 94720, USA.
Nature
|June 17, 2016
まとめ
ロカグラミドA (RocA) は,ユカリオット開始因子4A (eIF4A) を標的として,選択的に癌細胞を殺害する. この薬はeIF4Aを特定のRNA配列に絞り込み,タンパク質の合成を妨害し,癌細胞の発現を減少させます.
科学分野:
- 分子生物学
- 生物化学
- 癌 研究
背景:
- ロカグラミドA (RocA) はタンパク質合成を阻害し,アヌプロイド腫瘍細胞を選択的に標的とする.
- RocAは,ATP依存のRNAヘリコースであるエウカリオット開始因子4A (eIF4A) を標的にし,構造化されたmRNA5'未翻訳領域に対する選択性が示唆されている.
- 以前の仮説では,RocAはeIF4Aの可用性を減少させ,または構造化されたmRNA領域を標的として翻訳を抑制することを示唆していた.
研究 の 目的:
- RocAが選択的に翻訳を抑制する正確なメカニズムを解明する.
- RocAの作用メカニズムにおけるmRNA二次構造とeIF4Aの利用可能性の役割を調査する.
- RocAが特定のメッセンジャーRNAを標的にする際の選択性を決定する.
主な方法:
- eIF4A- RNAの相互作用を研究するためのインビトロ生化学測定法.
- 細胞ベースの実験で,翻訳抑制とタンパク質発現を評価する.
- RocAのeIF4A結合親和性とRNAヘリケース活性に対する影響の分析.
主要な成果:
- RocAの選択性は主にmRNA 5' 未翻訳領域の二次構造によって決定されません.
- RocAは,eIF4Aの可用性を低下させることで翻訳を抑制しません.
- RocAは,eIF4Aをポリプリン配列にATPから独立して固定し,43Sスキャニングを阻害し,早期の翻訳を開始します.
結論:
- RocAは,eIF4Aとポリプリン配列の間の配列特異的な相互作用を安定させることで,翻訳を選択的に抑制する.
- このメカニズムは,上流の翻訳開始と標的のトランスクリプトからのタンパク質発現の減少につながります.
- この研究は,治療効果のための配列選択性RNA-タンパク質相互作用の安定化薬の新しい例を提供します.
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