細胞内サルモネラ菌によるpH感知は,効果因子転位を誘導する
Xiu-Jun Yu1, Kieran McGourty, Mei Liu
1Section of Microbiology, Centre for Molecular Microbiology and Infection, Imperial College London, Armstrong Road, London SW7 2AZ, UK.
まとめ
サルモネラ・エンテリカは,第3型分泌システム (T3SS) を使用して,エフェクタタンパク質を注入します. この研究では,サルモネラ菌が宿主細胞のpHを感知してT3SSの機能とタンパク質の供給を調節することを明らかにしました.
科学分野:
- 微生物学 微生物学とは
- 細胞生物学 細胞生物学
- バクテリア病原菌の発生
背景:
- サルモネラ・エンテリカは,重要な細胞内病原体である.
- サルモネラ病原性島2 (SPI-2) 型III分泌システム (T3SS) を使用して,エフェクタタンパク質を宿主細胞に届けます.
- T3SSアセンブリは,真空中の酸性化に関連していますが,低pHでは効果分泌が低下しています.
研究 の 目的:
- サルモネラ菌におけるSPI-2 T3SSエフェクター分泌の調節を調査する.
- 分泌制御におけるSPI-2エンコードタンパク質 (SsaM,Spic,SsaL) の役割を明らかにする.
- サルモネラ菌が宿主細胞のpHを感知し,それに反応する方法を決定する.
主な方法:
- バクテリア培養は,異なるpH条件 (pH5.0と7.2) で培養する.
- SPI-2 T3SSタンパク質複合体の安定性 (SsaM, SpiC, SsaL) の分析について.
- エフェクタータンパク質分泌のモニタリング.
- 宿主細胞の感染と効果因子転移の評価.
主要な成果:
- SsaM,Spic,およびSsaL複合体を欠いた変異株は,低pHで活性化されたエフェクター分泌を示した.
- 低pH成長 (5.0) の後に中性pH (7.2) に暴露された野生型のサルモネラ菌は,複雑な解離,分解,およびエフェクター分泌を引き起こした.
- 宿主細胞のサイトゾールの酸性化により,感染した細胞における複雑な分解とエフェクター転位が防止されました.
結論:
- サルモネラ菌は宿主細胞 pH を感知する.
- ホストのpHを感知すると,調節性タンパク質複合体 (SsaM/SpiC/SsaL) の分解を誘発する.
- この分解は,宿主細胞へのエフェクター転移に不可欠です.
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