Laboratoire d'Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, UMR 7255, Marseille, France.
Mol Microbiol. 2021 Mar;115(3):383-394. doi: 10.1111/mmi.14648. Epub 2020 Dec 7.
The bacterial type VI secretion system (T6SS) system is a contractile secretion apparatus that delivers proteins to neighboring bacterial or eukaryotic cells. Antibacterial effectors are mostly toxins that inhibit the growth of other species and help to dominate the niche. A broad variety of these toxins cause cell lysis of the prey cell by disrupting the cell envelope. Other effectors are delivered into the cytoplasm where they affect DNA integrity, cell division or exhaust energy resources. The modular nature of T6SS machinery allows different means of recruitment of toxic effectors to secreted inner tube and spike components that act as carriers. Toxic effectors can be translationally fused to the secreted components or interact with them through specialized structural domains. These interactions can also be assisted by dedicated chaperone proteins. Moreover, conserved sequence motifs in effector-associated domains are subject to genetic rearrangements and therefore engage in the diversification of the arsenal of toxic effectors. This review discusses the diversity of T6SS secreted toxins and presents current knowledge about their loading on the T6SS machinery.
细菌的 VI 型分泌系统（T6SS）是一种可收缩的分泌装置，可将蛋白质递送到邻近的细菌或真核细胞。抗菌效应物主要是毒素，可抑制其他物种的生长，并有助于主导生态位。这些毒素的种类繁多，通过破坏细胞膜来导致靶细胞裂解。其他效应物被递送到细胞质中，在那里它们影响 DNA 完整性、细胞分裂或耗尽能量资源。T6SS 机械装置的模块化性质允许通过不同的方式招募毒性效应物到分泌的内管和刺突组件，这些组件充当载体。毒性效应物可以与分泌成分融合翻译，或者通过专门的结构域与它们相互作用。这些相互作用也可以由专门的伴侣蛋白辅助。此外，效应物相关结构域中的保守序列基序会发生遗传重排，从而参与到毒性效应物武器库的多样化中。这篇综述讨论了 T6SS 分泌毒素的多样性，并介绍了目前关于它们在 T6SS 机械装置上加载的知识。
