The Chlamydia trachomatis Early Effector Tarp Outcompetes Fascin in Forming F-Actin Bundles In Vivo.
The Chlamydia trachomatis Early Effector Tarp Outcompetes Fascin in Forming F-Actin Bundles In Vivo.
复制标题
沙眼衣原体早期效应子篷布在体内形成F-肌动蛋白束时筋膜蛋白质。
DOI：
10.3389/fcimb.2022.811407
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发表时间：
2022
影响因子：
5.7
通讯作者：
Jewett TJ
中科院分区：
文献类型：
--
作者：
Aranjuez GF;Kim J;Jewett TJ
细胞内病原体沙眼衣原体分泌多种早期效应物进入宿主细胞以促进侵袭。Tarp（translocated actin-recruiting phosphoprotein）是进入宿主细胞过程中的一个关键早期效应子，由多个蛋白质结构域组成，已知其在细胞信号传导、G-肌动蛋白成核和F-肌动蛋白束形成中发挥作用。在体外，由Tarp产生的肌动蛋白束是异常灵活的，然而，在体内，Tarp介导的肌动蛋白束的生物学意义仍然未知。我们推测Tarp产生独特肌动蛋白束的能力，在一定程度上促进了衣原体进入上皮细胞。为了研究Tarp和F-actin之间的体内相互作用，我们在果蝇组织中转基因表达Tarp。果蝇中表达的Tarp被磷酸化，并在组织中形成富含F-肌动蛋白的聚集体。为了深入了解Tarp肌动蛋白束在体内的意义，我们利用了在果蝇中的机械感觉刚毛发育的良好表征的模型系统。Tarp表达在野生型苍蝇产生弯曲的刚毛，表明在刚毛发育过程中的F-肌动蛋白动力学扰动。两个F-肌动蛋白的聚合物，烧焦/Fascin和分叉/Espin，是正常的鬃毛形状的重要。令人惊讶的是，Tarp在刚毛中的表达使Singed/Fascin远离F-肌动蛋白束。Tarp在F-actin捆绑过程中对Fascin的竞争行为在体外得到证实。苍蝇失去烧焦或分叉的鬃毛会导致鬃毛高度变形。引人注目的是，防水布部分挽救了烧焦的损失，减少了刷毛形态缺陷的严重程度。这项工作提供了在体内确认Tarp的F-肌动蛋白捆绑活动，并进一步揭示了在捆绑组装过程中对宿主生物标记物Singed/Fascin的竞争行为。此外，我们证明了果蝇作为体内细胞生物学平台研究细菌效应功能的实用性。
The intracellular pathogen Chlamydia trachomatis secretes multiple early effectors into the host cell to promote invasion. A key early effector during host cell entry, Tarp (translocated actin-recruiting phosphoprotein) is comprised of multiple protein domains known to have roles in cell signaling, G-actin nucleation and F-actin bundle formation. In vitro, the actin bundles generated by Tarp are uncharacteristically flexible, however, in vivo, the biological significance of Tarp-mediated actin bundles remains unknown. We hypothesize that Tarp’s ability to generate unique actin bundles, in part, facilitates chlamydial entry into epithelial cells. To study the in vivo interaction between Tarp and F-actin, we transgenically expressed Tarp in Drosophila melanogaster tissues. Tarp expressed in Drosophila is phosphorylated and forms F-actin-enriched aggregates in tissues. To gain insight into the significance of Tarp actin bundles in vivo, we utilized the well-characterized model system of mechanosensory bristle development in Drosophila melanogaster. Tarp expression in wild type flies produced curved bristles, indicating a perturbation in F-actin dynamics during bristle development. Two F-actin bundlers, Singed/Fascin and Forked/Espin, are important for normal bristle shape. Surprisingly, Tarp expression in the bristles displaced Singed/Fascin away from F-actin bundles. Tarp’s competitive behavior against Fascin during F-actin bundling was confirmed in vitro. Loss of either singed or forked in flies leads to highly deformed bristles. Strikingly, Tarp partially rescued the loss of singed, reducing the severity of the bristle morphology defect. This work provides in vivo confirmation of Tarp’s F-actin bundling activity and further uncovers a competitive behavior against the host bundler Singed/Fascin during bundle assembly. Also, we demonstrate the utility of Drosophila melanogaster as an in vivo cell biological platform to study bacterial effector function.