SidE family of Legionella effectors catalyze non-canonical phosphoribosyl-linked ubiquitination (PR-ubiquitination) of host proteins during bacterial infection. SdeA localizes predominantly to ER and partially to the Golgi apparatus, and mediates serine ubiquitination of multiple ER and Golgi proteins. Here we show that SdeA causes disruption of Golgi integrity due to its ubiquitin ligase activity. The Golgi linking proteins GRASP55 and GRASP65 are PR-ubiquitinated on multiple serine residues, thus preventing their ability to cluster and form oligomeric structures. In addition, we found that the functional consequence of Golgi disruption is not linked to the recruitment of Golgi membranes to the growing Legionella-containing vacuoles. Instead, it affects the host secretory pathway. Taken together, our study sheds light on the Golgi manipulation strategy by which Legionella hijacks the secretory pathway and promotes bacterial infection.

军团菌效应子的 SideE 家族在细菌感染期间催化宿主蛋白的非典型磷酸核糖基泛素化（PR-泛素化）。SdeA 主要定位于 ER，部分定位于高尔基体，并介导多种 ER 和高尔基体蛋白的丝氨酸泛素化。在这里，我们显示 SdeA 由于其泛素连接酶活性而导致高尔基体完整性的破坏。高尔基连接蛋白 GRASP55 和 GRASP65 在多个丝氨酸残基上被 PR 泛素化，从而阻止了它们聚集和形成寡聚结构的能力。此外，我们发现高尔基体破坏的功能后果与将高尔基体膜募集到生长中的军团菌无关-含有液泡。相反，它会影响宿主分泌途径。总之，我们的研究揭示了军团菌劫持分泌途径并促进细菌感染的高尔基体操纵策略。