1. Identification of homologs of the Chlamydia trachomatis effector CteG reveals a family of Chlamydiaceae type III secreted proteins that can be delivered into host cells.
- Author
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Pereira IS, da Cunha M, Leal IP, Luís MP, Gonçalves P, Gonçalves C, and Mota LJ
- Subjects
- Humans, Virulence Factors metabolism, Virulence Factors genetics, HeLa Cells, Yersinia genetics, Yersinia metabolism, Protein Transport, Host-Pathogen Interactions, Evolution, Molecular, Chlamydiaceae genetics, Chlamydiaceae metabolism, Chlamydiaceae classification, Chlamydia trachomatis genetics, Chlamydia trachomatis metabolism, Bacterial Proteins metabolism, Bacterial Proteins genetics, Phylogeny, Type III Secretion Systems metabolism, Type III Secretion Systems genetics
- Abstract
Chlamydiae are a large group of obligate endosymbionts of eukaryotes that includes the Chlamydiaceae family, comprising several animal pathogens. Among Chlamydiaceae, Chlamydia trachomatis causes widespread ocular and urogenital infections in humans. Like many bacterial pathogens, all Chlamydiae manipulate host cells by injecting them with type III secretion effector proteins. We previously characterized the C. trachomatis effector CteG, which localizes at the host cell Golgi and plasma membrane during distinct phases of the chlamydial infectious cycle. Here, we show that CteG is a Chlamydiaceae-specific effector with over 60 homologs phylogenetically categorized into two distinct clades (CteG I and CteG II) and exhibiting several inparalogs and outparalogs. Notably, cteG I homologs are syntenic to C. trachomatis cteG, whereas cteG II homologs are syntenic among themselves but not with C. trachomatis cteG. This indicates a complex evolution of cteG homologs, which is unique among C. trachomatis effectors, marked by numerous events of gene duplication and loss. Despite relatively modest sequence conservation, nearly all tested CteG I and CteG II proteins were identified as type III secretion substrates using Yersinia as a heterologous bacterial host. Moreover, most of the type III secreted CteG I and CteG II homologs were delivered by C. trachomatis into host cells, where they localized at the Golgi region and cell periphery. Overall, this provided insights into the evolution of bacterial effectors and revealed a Chlamydiaceae family of type III secreted proteins that underwent substantial divergence during evolution while conserving the capacity to localize at specific host cell compartments., (© 2024. The Author(s).)
- Published
- 2024
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