CtIncipedia – A multidisciplinary approach to study Chlamydia trachomatis inclusion membrane (Inc) proteins

Financiador

Organização

Publicações

Manipulation of host cells by Chlamydia trachomatis: function and subcellular localization of an inclusion membrane protein

Publication . Luís, Maria Silva Filipe Pequito; Mota, Luís

Chlamydia trachomatis is an obligate intracellular bacterial pathogen that causes ocular and genital infections of major burden worldwide. Once inside host cells, C. trachomatis resides within a specialized vacuole, known as an inclusion. From within the inclusion, C. trachomatis utilizes a type III secretion system to transport effector proteins into the host cell which subvert many cellular processes. Among these effectors, there is a large group, termed Incs, which insert at the inclusion membrane. In this work, to advance the understanding on molecular and cellular mechanisms underlying C. trachomatis virulence, we focused on characterizing the role of Inc CT288/CTL0540 (renamed IncM). We showed that IncM is conserved among mostChlamydia species, highlighting its evolutionary significance. At a functional level, we revealed that IncM participates in the ability of Chlamydia to inhibit host cytokinesis, dislocate centrosomes, and redistribute the Golgi complex around the inclusion. IncM also showed to contribute to the maintenance of the inclusion morphology and stability, and the circularity of IncM-deficient inclusions was specifically sensitive to microtubule depolymerization. Overall, these findings suggested that IncM may exert its effector function by acting directly or indirectly on host microtubules. We also found an intriguing role of the promoter used for inc gene expression regarding the exact localization of IncM and other Incs (IncD and InaC). This led us to identify three novel bona fide Incs (CT195, CT214, and CT484). In summary, by detailing the function of IncM, this work increased the understanding of how C. trachomatis manipulates host cells through its effectors. It also suggests future studies on how IncM acts on host microtubules, how the novel identified Incs function, and how gene expression within the chlamydiae can dictate an exact protein localization at the inclusion membrane.

2024Tese de doutoramento

Acesso aberto

Ver mais

The Chlamydia trachomatis IncM Protein Interferes with Host Cell Cytokinesis, Centrosome Positioning, and Golgi Distribution and Contributes to the Stability of the Pathogen-Containing Vacuole

Publication . Luís, Maria Pequito; Pereira, Inês Serrano; Bugalhão, Joana N.; Simões, Catarina N.; Mota, Cristiano; Romão, Maria João; Mota, Luís Jaime; DCV - Departamento de Ciências da Vida; UCIBIO - Applied Molecular Biosciences Unit; DQ - Departamento de Química; American Society for Microbiology

Chlamydia trachomatis is an obligate intracellular bacterial pathogen that causes ocular and urogenital infections in humans. The ability of C. trachomatis to grow intracellularly in a pathogen-containing vacuole (known as an inclusion) depends on chlamydial effector proteins transported into the host cell by a type III secretion system. Among these effectors, several inclusion membrane proteins (Incs) insert in the vacuolar membrane. Here, we show that human cell lines infected by a C. trachomatis strain deficient for Inc CT288/CTL0540 (renamed IncM) displayed less multinucleation than when infected by IncM-producing strains (wild type or complemented). This indicated that IncM is involved in the ability of Chlamydia to inhibit host cell cytokinesis. The capacity of IncM to induce multinucleation in infected cells was shown to be conserved among its chlamydial homologues and appeared to require its two larger regions predicted to be exposed to the host cell cytosol. C. trachomatis-infected cells also displayed IncM-dependent defects in centrosome positioning, Golgi distribution around the inclusion, and morphology and stability of the inclusion. The altered morphology of inclusions containing IncM-deficient C. trachomatis was further affected by depolymerization of host cell microtubules. This was not observed after depolymerization of microfilaments, and inclusions containing wild-type C. trachomatis did not alter their morphology upon depolymerization of microtubules. Overall, these findings suggest that IncM may exert its effector function by acting directly or indirectly on host cell microtubules.

2023-04-18Artigo científico

Acesso aberto

Ver mais

CteG, a Chlamydia trachomatis protein involved in host cell lytic exit

Publication . Pereira, Inês Isabel Serrano; Mota, Luís

The Phylum Chlamydiae comprises bacteria that only multiply inside eukaryotic host cells, within a membrane-bound vacuole. Among Chlamydiae, the Family Chlamydiaceae includes Chlamydia trachomatis, a major human pathogen causing ocular and genital infections. The characteristic infectious cycle of Chlamydiae involves chlamydial-mediated host cell invasion and egress. Throughout the cycle, Chlamydiae subvert host cell processes through effector proteins delivered into host cells by a type III secretion system. Previously, it was shown that the C. trachomatis CteG effector localizes at the Golgi and plasma membrane of infected cells. Moreover, the first 100 residues of CteG fused to EGFP (EGFP-CteG100) localize at the Golgi upon their ectopic expression in mammalian cells. In this work, we found that CteG mediates C. trachomatis host cell lytic exit. Cells infected by a CteG-deficient strain showed less chlamydiae in the culture supernatant and displayed lower levels of cytotoxicity comparing to cells infected by CteG-producing wild-type and complemented strains. We further showed that CteG and Pgp4, a global regulator of transcription encoded in the C. trachomatis virulence plasmid, act on the same pathway leading to chlamydial host cell lytic exit. We also found a predicted α-helix on the N-terminal region of CteG that is essential for the localization of ectopically expressed EGFP-CteG100 at the Golgi and plays a role in adequate targeting of CteG to the Golgi and plasma membrane in infected cells. Finally, we identified host cell proteins that may interact with CteG and provided insights into the evolutionary history of cteG by bioinformatics analysis of its homologs in Chlamydiaceae. In summary, this work revealed a role of CteG in C. trachomatis host cell exit, a crucial step of the chlamydial infectious cycle. Together with other findings, this expanded the knowledge on C. trachomatis-host cell interactions and opened avenues for future research.

2022Tese de doutoramento

Acesso aberto

Ver mais

Identification and characterization of CteG, a novel Chlamydia trachomatis type III

Publication . Pais, Sara Raquel Vilela; Mota, Luís

2018-12-20Tese de doutoramento

Acesso aberto

Ver mais