报告题目：ADP-ribosylation, ubiquitination and beyond by Legionella virulence factors

报告人：罗招庆, Ph.D.   Department of Biological Sciences, Purdue University

时间：2023年7月11日（星期二）上午10:00

地点：植保楼2060A

联系人：张力群

报告人简介：

    罗招庆教授长期从事细菌致病机理的研究，在细菌效应蛋白的发现、鉴定及其作用的生化和细胞生物学机制等方面取得了一系列原创性研究成果。团队近年来揭示了一种细菌效应蛋白催化的全新蛋白质泛素化修饰及其调控，该泛素化过程不需要经典修饰必需的E1和E2酶的参与，而是以NAD为能量源，通过ADP核糖基化激活泛素。该研究开创了一个全新的泛素化研究领域，对揭示该修饰在细胞信号转导、疾病发生等方面的功能具有重要意义。研究成果以通讯作者在Nature（3篇），Nature Microbiology, PNAS（6篇），Cell Research，PLoS Pathogens（6篇）等期刊发表论文90余篇，并受邀为Nature Reviews Microbiology，journal of Cell Biology, Molecular Cell, EMBO Reports等撰写相关综述和评论。目前担任病原学杂志PLoS Pathogens及 mLife的Associate Editor。

Abstract: 

    Our earlier work found that members of the SidE family (SidEs) of Legionella pneumophila induce ubiquitination via a mechanism that is chemically distinct from the canonical E1-E2-E3 cascade. Reactions induced by SidEs and the reversal of the modification by specific enzymes produce ADP-ribosylated ubiquitin (ADPR-Ub) and phosphoribosyl ubiquitin (PR-Ub), none of which can be utilized in canonical ubiquitination, thus may interfere with host ubiquitin homeostasis. We found that the bacterium resolves this conundrum by sequential biochemical reactions to return modified ubiquitin to its native form. Furthermore, we found that the catalytic mechanism of one of these effectors appears to be widely used by toxins from diverse pathogens, highlighting a potentially universal mechanism in host-pathogen interactions and in signaling of host cells. 

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