Wesolowski Jordan, Weber Mary M, Nawrotek Agata, Dooley Cheryl A, Calderon Mike, St Croix Claudette M, Hackstadt Ted, Cherfils Jacqueline, Paumet Fabienne
Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
Host-Parasite Interactions Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
mBio. 2017 May 2;8(3):e02280-16. doi: 10.1128/mBio.02280-16.
The intracellular bacterium develops in a parasitic compartment called the inclusion. Posttranslationally modified microtubules encase the inclusion, controlling the positioning of Golgi complex fragments around the inclusion. The molecular mechanisms by which coopts the host cytoskeleton and the Golgi complex to sustain its infectious compartment are unknown. Here, using a genetically modified strain, we discovered that both posttranslationally modified microtubules and Golgi complex positioning around the inclusion are controlled by the chlamydial inclusion protein CT813/CTL0184/InaC and host ARF GTPases. CT813 recruits ARF1 and ARF4 to the inclusion membrane, where they induce posttranslationally modified microtubules. Similarly, both ARF isoforms are required for the repositioning of Golgi complex fragments around the inclusion. We demonstrate that CT813 directly recruits ARF GTPases on the inclusion membrane and plays a pivotal role in their activation. Together, these results reveal that uses CT813 to hijack ARF GTPases to couple posttranslationally modified microtubules and Golgi complex repositioning at the inclusion. is an important cause of morbidity and a significant economic burden in the world. However, how develops its intracellular compartment, the so-called inclusion, is poorly understood. Using genetically engineered mutants, we discovered that the effector protein CT813 recruits and activates host ADP-ribosylation factor 1 (ARF1) and ARF4 to regulate microtubules. In this context, CT813 acts as a molecular platform that induces the posttranslational modification of microtubules around the inclusion. These cages are then used to reposition the Golgi complex during infection and promote the development of the inclusion. This study provides the first evidence that ARF1 and ARF4 play critical roles in controlling posttranslationally modified microtubules around the inclusion and that hijacks this novel function of ARF to reposition the Golgi complex.
这种细胞内细菌在一种称为包涵体的寄生区室中发育。翻译后修饰的微管包裹着包涵体，控制着高尔基体复合体片段在包涵体周围的定位。该细菌如何利用宿主细胞骨架和高尔基体复合体来维持其感染区室的分子机制尚不清楚。在这里，我们使用一种基因改造的菌株，发现翻译后修饰的微管和高尔基体复合体在包涵体周围的定位均受衣原体包涵体蛋白CT813/CTL0184/InaC和宿主ARF GTP酶的控制。CT813将ARF1和ARF4募集到包涵体膜上，在那里它们诱导翻译后修饰的微管形成。同样，两种ARF亚型对于高尔基体复合体片段在包涵体周围的重新定位也是必需的。我们证明CT813直接在包涵体膜上募集ARF GTP酶，并在其激活过程中起关键作用。总之，这些结果表明该细菌利用CT813劫持ARF GTP酶，以在包涵体处将翻译后修饰的微管与高尔基体复合体重新定位联系起来。该细菌是全球发病的一个重要原因，也是一项重大的经济负担。然而，人们对其如何形成细胞内区室即所谓的包涵体知之甚少。利用基因工程改造的突变体，我们发现效应蛋白CT813募集并激活宿主ADP核糖基化因子1（ARF1）和ARF4来调节微管。在这种情况下，CT813充当一个分子平台，诱导包涵体周围微管的翻译后修饰。然后这些“笼子”在感染期间用于重新定位高尔基体复合体，并促进包涵体的发育。这项研究首次证明ARF1和ARF4在控制包涵体周围翻译后修饰的微管方面起关键作用，并且该细菌劫持ARF的这一新功能来重新定位高尔基体复合体。
