Mechanism of atypical ubiquitination and deubiquitination by bacterial effectors

细菌效应子的非典型泛素化和去泛素化机制

• 批准号: 10389794
• 负责人: Chittaranjan Das
• 金额: $ 4.67万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-01-16 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10389794
• 关键词: Biochemical; Biological; Cell physiology; Detection; Deubiquitination; Enzymes; Eukaryota; Event; Family; Infection; Legionella pneumophila; Legionnaires' Disease; Prevention strategy; Proteins; Reaction; Side; Signal Transduction; Structure; Ubiquitin; Ubiquitination; Virulence; Work; infectious disease treatment; member; novel; novel strategies; pathogen; pathogenic bacteria; response; success; virtual

Project summary Active modulation of host function is essential for the success of bacterial pathogens. The ubiquitin network regulates virtually every cellular process in eukaryotes, particularly those involved in the detection, recognition and response to infection. Accordingly, many pathogens target host ubiquitination for their benefits. Earlier studies revealed that Legionella pneumophila, the causative agent of Legionnaires' disease, interferes with host ubiquitin signaling by using at least 9 of its Dot/Icm effectors. Our recent study revealed that members of the SidE effector family feature enzymatic domains with unique activities for manipulating ubiquitin signals. First, these proteins contain a deubiquitinase (DUB) module that efficiently removes ubiquitin from ubiquitinated proteins. Second, these proteins catalyze ubiquitination by an unusual mechanism: the reaction does not require the E1, E2 enzymes or ATP, factors that are essential for all described ubiquitination events. Furthermore, these novel ubiquitin manipulating effectors are required for maximal intracellular bacterial replication, which differs sharply with the majority of L. pneumophila Dot/Icm type IV effectors. As an additional layer of complexity, we find that the biological activity of SidE effectors is regulated by the SidJ effector through its reversal of the SidE-catalyzed ubiquitination by a mechanism that appears to distinctly differ from classical DUBs. By biochemical and structural analyses, we will study the mechanism of action of these proteins. Different functional domains encoded in these effectors seem to work in concert to regulate each other for a balanced control of host functions. We will study biochemical basis of functional integration among distinct activities present within these effectors. These studies will not only reveal novel mechanisms of host function exploitation by intracellular pathogens, but also will have the potential to revise the current understanding of ubiquitination, an enormously important signaling mechanism.

项目摘要 主机功能的主动调节对于细菌病原体的成功至关重要。泛素 网络几乎调节真核生物中的每个蜂窝过程，尤其是参与 检测，识别和对感染的反应。因此，许多病原体靶宿主泛素化 为了他们的利益。较早的研究表明，肺炎军团菌，是 军团疾病通过使用至少9个点/ICM效应子来干扰宿主的泛素信号传导。 我们最近的研究表明，副作用家族的成员具有酶促结构域 操纵泛素信号的独特活动。首先，这些蛋白质含有去泛素酶（DUB） 从泛素化蛋白中有效去除泛素的模块。第二，这些蛋白质催化 通过一种异常机制的泛素化：反应不需要E1，E2酶或ATP， 对于所有描述的泛素化事件至关重要的因素。此外，这些新颖的泛素 最大细胞内细菌复制需要操纵效应子，这急剧不同 大多数肺炎乳杆菌点/ICM IV型效应子。作为额外的复杂性，我们 发现副作用的生物学活性受SIDJ效应器的调节，其逆转 通过一种与经典配音明显不同的机制，侧催化的泛素化。经过 生化和结构分析，我们将研究这些蛋白质的作用机理。不同的 这些效应子中编码的功能域似乎协同起作用以相互调节以进行 主机功能的平衡控制。我们将研究功能整合的生化基础 这些效应子中存在的不同活动。这些研究不仅会揭示 细胞内病原体的宿主功能开发，但也有可能修改电流 了解泛素化，这是一种非常重要的信号传导机制。