细胞内沙门氏菌的pH感应诱导了效应因子转位
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.
概括
沙门氏菌使用一种III型分泌系统 (T3SS) 来注入效应蛋白. 这项研究表明,沙门氏菌感知宿主细胞的pH值,以调节T3SS功能和蛋白质输送.
科学领域:
- 微生物学 微生物学
- 细胞生物学 细胞生物学
- 细菌病原体的产生
背景情况:
- 沙门氏菌 (Salmonella enterica) 是一个重要的细胞内病原体.
- 它利用沙门氏菌病原性岛2 (SPI-2) 型III分泌系统 (T3SS) 输送效应蛋白到宿主细胞中.
- T3SS组件与真空酸性化有关,但在低pH下,效应体分泌会受到损害.
研究的目的:
- 为了研究沙门氏菌中SPI-2 T3SS效应体分泌的调节.
- 阐明SPI-2编码蛋白 (SsaM,Spic,SsaL) 在分泌控制中的作用.
- 为了确定沙门氏菌如何感知和响应宿主细胞的pH值.
主要方法:
- 在不同的pH条件下培养细菌 (pH为5.0和7.2).
- 对SPI-2 T3SS蛋白质复合体稳定性的分析 (SsaM,Spic,SsaL).
- 对效应蛋白分泌的监测.
- 宿主细胞的感染和效应因子转移的评估.
主要成果:
- 缺乏SsaM,Spic和SsaL复合体的突变菌株在低pH值时显示出激活的效应体分泌.
- 在低pH增长 (5.0) 后暴露于中性pH (7.2) 的野生型沙门氏菌导致复杂的解离,降解和效应物分泌.
- 宿主细胞细胞醇的酸化阻止了复杂的降解和受感染细胞中的效应体转移.
结论:
- 静脉内沙门氏菌感知宿主细胞 pH.
- 感知宿主pH值会触发调节性蛋白质复合体 (SsaM/SpiC/SsaL) 的降解.
- 这种降解对于效应体转移到宿主细胞至关重要.
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