The ubiquitin system is an important part of the host cellular defense program during bacterial infection. This is in particular evident for a number of bacteria including Salmonella Typhimurium and Mycobacterium tuberculosis which—inventively as part of their invasion strategy or accidentally upon rupture of seized host endomembranes—become exposed to the host cytosol. Ubiquitylation is involved in the detection and clearance of these bacteria as well as in the activation of innate immune and inflammatory signaling. Remarkably, all these defense responses seem to emanate from a dense layer of ubiquitin which coats the invading pathogens. In this review, we focus on the diverse group of host cell E3 ubiquitin ligases that help to tailor this ubiquitin coat. In particular, we address how the divergent ubiquitin conjugation mechanisms of these ligases contribute to the complexity of the anti-bacterial coating and the recruitment of different ubiquitin-binding effectors. We also discuss the activation and coordination of the different E3 ligases and which strategies bacteria evolved to evade the activities of the host ubiquitin system.

中文翻译：

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防御细菌病原体中的泛素连接机制

泛素系统是细菌感染期间宿主细胞防御程序的重要组成部分。这对于包括鼠伤寒沙门氏菌和结核分枝杆菌在内的许多细菌尤其明显它——创造性地作为它们入侵策略的一部分，或者在被捕获的宿主内膜破裂时意外地——暴露于宿主细胞质中。泛素化参与这些细菌的检测和清除以及先天免疫和炎症信号传导的激活。值得注意的是，所有这些防御反应似乎都来自覆盖入侵病原体的致密泛素层。在这篇综述中，我们专注于帮助定制这种泛素涂层的宿主细胞 E3 泛素连接酶的不同组。特别是，我们解决了这些连接酶的不同泛素缀合机制如何导致抗菌涂层的复杂性和不同泛素结合效应子的募集。