AB5サブティラゼサイトトキシンは,エンドプラズマ網膜のチャペロンBiPを無効化する
Adrienne W Paton1, Travis Beddoe, Cheleste M Thorpe
1School of Molecular and Biomedical Science, University of Adelaide, South Australia 5005, Australia. adrienne.paton@adelaide.edu.au
Nature
|October 7, 2006
まとめ
バクテリアの毒素であるサブティラゼ・サイトトキシン (Subtilase cytotoxin) は,必要不可欠なエンドプラズマ網膜のチャペロンBiP/GRP78.8を割って細胞死を誘発する. この特定の割れ目が正常な細胞機能を破壊し,細菌の病原性の新しいメカニズムを強調しています.
科学分野:
- 微生物学 微生物学とは
- 細胞生物学 細胞生物学
- 毒理学 毒理学 毒理学
背景:
- AB5毒素は,酵素性Aサブユニットと細胞吸収を媒介するBサブユニットで構成された細菌の毒性因子です.
- 既知のAB5毒素には,Shiga,コレラ, pertussisの毒素が含まれています.
- サブティラゼ・サイトトキシン (Subtilase cytotoxin) は,シガ毒性エシェリキア・コリ菌から最近特定された第4族のAB5毒素である.
研究 の 目的:
- サブティラゼ・サイトトキシンの極端なサイト毒性の背後にあるメカニズムを解明する.
- サブティラゼ・サイトトキシンの特定の細胞標的と分裂部位を特定するために.
- サブティラゼ細胞毒素誘発細胞死におけるBiP/GRP78の役割を調査する.
主な方法:
- サブティラゼサイトトキシンAサブユニットの構造研究.
- BiP/GRP78を基質として使用したインビトロ割れ分析.
- サイト指向型変異は,BiPの標的部位を変化させる.
- 細胞ベースの測定法で,細胞毒性と保護を評価する.
主要な成果:
- サブティラゼ・サイトトキシン (subtilase cytotoxin) は,エンドプラズマ網膜のチャペロンBiP/GRP78を単一の部位で特に割る.
- 構造分析により,Aサブユニットに深いアクティブサイト裂け目が明らかになり,基質特異性が説明されました.
- BiPの標的部位における単一のアミノ酸置換により,BiPは割れに抵抗するようになった.
- サブティラゼ・サイトトキシンから保護された抵抗性BiP細胞の共発現.
結論:
- BiP/GRP78のサブティラゼ・サイトトキシンによる割れは,その高いサイト毒性の主要な原因である.
- これは,細菌の毒素が,エンドプラズマ網膜の恒常性を破壊することによって細胞死を誘発する新しいメカニズムを表しています.
- BiP/GRP78の割れ目をターゲットにすることは,サブティラゼ・サイトトキシンに対する治療的介入のための潜在的な戦略を提供します.
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