军团菌的T4bSS具有两步分泌途径,其中一个是内膜中间体,用于分泌跨膜效应器
Silke Malmsheimer1, Iwan Grin1, Erwin Bohn2
1University of Tübingen, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Section of Cellular and Molecular Microbiology, Tübingen, Germany.
PLoS pathogens
|November 15, 2024
概括
肺炎菌使用IV型b分泌系统 (T4bSS) 将含有跨膜域的效应物注入宿主细胞. 这些疏水性蛋白质通过两步过程分泌,包括内膜插入和T4bSS介导的转位.
科学领域:
- 微生物学 微生物学
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
背景情况:
- 军团菌种 (Legionella spp.) 是一种病毒. 使用IV型b分泌系统 (T4bSS) 将效应蛋白转移到宿主细胞中,以实现细胞内生存.
- 已知T4bSS分泌可溶和跨膜域含有效应蛋白 (TMD-效应蛋白),但分泌机制尚不清楚.
- 大约有80个TMD效应因子被Legionella pneumophila编码,这突显了它们在病原发生中的重要性.
研究的目的:
- 为了研究水性TMD-effector的分泌机制,由莱吉欧内拉肺炎菌.
- 阐明T4bSS陪伴者 (ICMS和ICMW) 和分泌信号在TMD效应器转位中的作用.
- 了解TMD效应器的向和插入到细菌内膜中的方法.
主要方法:
- 分裂细菌膜的蛋白质组分析.
- 调查TMD-effector的向和插入在存在和缺失的功能性T4bSS.
- 在TMD效应器转位中对C端分泌信号和周等离子环的功能分析.
- 评估T4bSS陪伴者ICMS和ICMW对TMD-effector分泌物的影响.
主要成果:
- TMD 效应器是针对细菌的内膜并插入其中的,独立于功能性的 T4bSS.
- T4bSS陪伴者ICMS和ICMW对于TMD效应器分泌是必不可少的,但对于内膜准不是必要的.
- 转移TMD效应器需要一个C端分泌信号,它必须暴露在细胞质侧.
- 对于高效的TMD-effector转位,需要一个小的周等离子循环,这表明有两步分泌机制.
结论:
- 莱吉欧内拉肺炎菌采用了对疏水性TMD效应体的两步分泌过程.
- 第一步涉及内膜向和插入,随后是T4bSS介导的转位.
- T4bSS在分泌来自各种亚细胞位置的效应剂方面表现出了显著的多功能性.
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