Regulation of phosphoribosyl ubiquitination by a calmodulin-dependent glutamylase
Regulation of phosphoribosyl ubiquitination by a calmodulin-dependent glutamylase
复制标题
钙调蛋白依赖性谷氨酰胺酶对磷酸核糖泛素化的调节
DOI：
10.1038/s41586-019-1439-1
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发表时间：
2019-08-15
期刊：
影响因子：
64.8
通讯作者：
Luo, Zhao-Qing
中科院分区：
文献类型：
--
作者：
Gan, Ninghai;Zhen, Xiangkai;Luo, Zhao-Qing
细菌病原体嗜肺军团菌使用其 Dot/Icm 分泌系统传递的数百种效应蛋白广泛调节宿主细胞功能，从而创建了一个允许其复制的细胞内生态位 (1)。其中，SidE 家族 (SidEs) 的成员通过绕过经典泛素化机制的独特磷酸核糖泛素化机制来调节多种细胞过程(2-4)。 SidEs 的活性由另一种称为 SidJ(5) 的 Dot/Icm 效应器调节；然而，这种调节的机制尚不完全清楚(6,7)。在这里，我们证明 SidJ 通过诱导谷氨酸部分与 SdeA（SidE 家族成员）在 E860 处共价连接来抑制 SidE 的活性，SdeA 是参与泛素激活的单 ADP 核糖基转移酶活性所需的催化残基之一 (2)。 SidJ 的这种抑制作用在宿主细胞中受到空间限制，因为其活性需要真核生物特异性蛋白钙调蛋白 (CaM)。我们解析了 SidJ-CaM 与 AMP 复合物的结构，发现该反应中使用的 ATP 在 a-磷酸位置被 SidJ 裂解，在没有谷氨酸或可修饰的 SdeA 的情况下，SidJ 会发生自 AMPylation。我们的结果揭示了细菌致病性的调节机制，其中抑制毒力因子活性的谷氨酰化反应是由宿主因子依赖性酰基腺苷酸化激活的。
The bacterial pathogen Legionella pneumophila creates an intracellular niche permissive for its replication by extensively modulating host-cell functions using hundreds of effector proteins delivered by its Dot/Icm secretion system(1). Among these, members of the SidE family (SidEs) regulate several cellular processes through a unique phosphoribosyl ubiquitination mechanism that bypasses the canonical ubiquitination machinery(2-4). The activity of SidEs is regulated by another Dot/Icm effector known as SidJ(5); however, the mechanism of this regulation is not completely understood(6,7). Here we demonstrate that SidJ inhibits the activity of SidEs by inducing the covalent attachment of glutamate moieties to SdeA-a member of the SidE family-at E860, one of the catalytic residues that is required for the mono-ADP-ribosyltransferase activity involved in ubiquitin activation(2). This inhibition by SidJ is spatially restricted in host cells because its activity requires the eukaryote-specific protein calmodulin (CaM). We solved a structure of SidJ-CaM in complex with AMP and found that the ATP used in this reaction is cleaved at the a-phosphate position by SidJ, which-in the absence of glutamate or modifiable SdeA-undergoes self-AMPylation. Our results reveal a mechanism of regulation in bacterial pathogenicity in which a glutamylation reaction that inhibits the activity of virulence factors is activated by host-factor-dependent acyl-adenylation.