The Mosaic Type IV Secretion Systems.
The Mosaic Type IV Secretion Systems.
复制标题
DOI：
10.1128/ecosalplus.esp-0020-2015
复制
发表时间：
2016-10
期刊：
影响因子：
--
通讯作者：
Christie PJ
中科院分区：
文献类型：
--
作者：
Christie PJ
大肠杆菌和其他革兰氏阴性和阳性细菌使用IV型分泌系统（T4SS）来将DNA和蛋白质底物转运至其他细胞，通常通过接触依赖性机制。T4SS在功能上包括两个主要的亚家族，缀合系统和效应物易位子。接合系统负责抗生素抗性基因、毒力决定因子和编码对细菌宿主潜在有益的其他性状的基因的细菌间转移。许多革兰氏阴性病原体在感染过程中使用效应物转位器将潜在的数百种称为效应物的毒力蛋白递送到真核细胞。在大肠大肠杆菌和肠杆菌科其它物种中，迄今鉴定的T4SS仅在接合DNA转移中起作用。在这些物种中，质粒编码系统可分为P、F和I型。P型系统在亚基组成和结构方面是最简单的，并且该亚家族的成员与典型的根癌农杆菌VirB/VirD4 T4SS共享共同的特征。本文将总结我们目前对E. coli系统和A.根癌农杆菌P型系统，重点是T4SSs的结构多样性。祖先的P-，F-和I-型系统在整个进化过程中进行了调整，以产生现存的效应器移位器，以及有关其特征的效应器移位器的信息也包括在内，以进一步说明这些高度通用的机器的适应性和马赛克性质。
Escherichia coli and other Gram-negative and -positive bacteria employ type IV secretion systems (T4SSs) to translocate DNA and protein substrates, generally by contact-dependent mechanisms, to other cells. The T4SSs functionally encompass two major subfamilies, the conjugation systems and the effector translocators. The conjugation systems are responsible for interbacterial transfer of antibiotic resistance genes, virulence determinants, and genes encoding other traits of potential benefit to the bacterial host. The effector translocators are used by many Gram-negative pathogens for delivery of potentially hundreds of virulence proteins termed effectors to eukaryotic cells during infection. In E. coli and other species of Enterobacteriaceae, T4SSs identified to date function exclusively in conjugative DNA transfer. In these species, the plasmid-encoded systems can be classified as the P, F, and I types. The P-type systems are the simplest in terms of subunit composition and architecture, and members of this subfamily share features in common with the paradigmatic Agrobacterium tumefaciens VirB/VirD4 T4SS. This review will summarize our current knowledge of the E. coli systems and the A. tumefaciens P-type system, with emphasis on the structural diversity of the T4SSs. Ancestral P-, F-, and I-type systems were adapted throughout evolution to yield the extant effector translocators, and information about well-characterized effector translocators also is included to further illustrate the adaptive and mosaic nature of these highly versatile machines.