Effector loading onto the VgrG carrier activates type VI secretion system assembly
Effector loading onto the VgrG carrier activates type VI secretion system assembly
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DOI：
10.15252/embr.201947961
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发表时间：
2019-12
期刊：
影响因子：
7.7
通讯作者：
Chih-Feng Wu;Yun-Wei Lien;Devanand Bondage;Jer-Sheng Lin;M. Pilhofer;Y. Shih;Jeff H. Chang;E. Lai-E.-La
中科院分区：
文献类型：
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作者：
Chih-Feng Wu;Yun-Wei Lien;Devanand Bondage;Jer-Sheng Lin;M. Pilhofer;Y. Shih;Jeff H. Chang;E. Lai-E.-La
VI型分泌系统（T6SS）被许多细菌用于参与社会行为，并可能影响其宿主植物或动物的健康。由于与T6SS相关的活动通常成本高昂，因此必须对T6SS进行严格监管。然而，我们对T6SS组装和收缩如何调节的了解仍然有限。使用植物病原体根癌农杆菌，我们表明，效应不只是乘客，但也影响T6SS组装。助理根癌农杆菌菌株C58编码一个T6SS和两个Tde DNA酶毒素效应子，其用作细菌间竞争的主要武器。在这里，我们表明，加载Tde效应到其同源载体，VgrG尖峰，是必需的主动T6SS分泌。TssBC收缩鞘的组装仅在Tde效应物存在下发生。在其他A.根瘤菌菌株。我们建议，这样的机制是由细菌作为有效的T6SS发射的策略，并确保效应器加载到T6SS完成其组装之前。
The type VI secretion system (T6SS) is used by many bacteria to engage in social behavior and can affect the health of its host plant or animal. Because activities associated with T6SSs are often costly, T6SSs must be tightly regulated. However, our knowledge regarding how T6SS assembly and contraction are regulated remains limited. Using the plant pathogen Agrobacterium tumefaciens, we show that effectors are not just passengers but also impact on T6SS assembly. The A. tumefaciens strain C58 encodes one T6SS and two Tde DNase toxin effectors used as major weapons for interbacterial competition. Here, we demonstrate that loading of Tde effectors onto their cognate carriers, the VgrG spikes, is required for active T6SS secretion. The assembly of the TssBC contractile sheath occurs only in the presence of Tde effectors. The requirement of effector loading for efficient T6SS secretion was also validated in other A. tumefaciens strains. We propose that such a mechanism is used by bacteria as a strategy for efficacious T6SS firing and to ensure that effectors are loaded onto the T6SS prior to completing its assembly.