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    Pathogen-host reorganisation during Chlamydia invasion revealed by cryo-electron tomography

    Nans, Andrea and Saibil, Helen R. and Hayward, Richard (2014) Pathogen-host reorganisation during Chlamydia invasion revealed by cryo-electron tomography. Cellular Microbiology 16 (10), pp. 1457-1472. ISSN 1462-5814.

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    Invasion of host cells is a key early event during bacterial infection, but the underlying pathogen-host interactions are yet to be fully visualised in three-dimensional detail. We have captured snapshots of the early stages of bacterial-mediated endocytosis in situ by exploiting the small size of chlamydial elementary bodies (EBs) for whole cell cryo-electron tomography. Chlamydiae are obligate intracellular bacteria that infect eukaryotic cells and cause sexually transmitted infections and trachoma, the leading cause of preventable blindness. We demonstrate that Chlamydia trachomatis LGV2 EBs are intrinsically polarised. One pole is characterised by a tubular inner membrane invagination, while the other exhibits asymmetric periplasmic expansion to accommodate an array of type III secretion systems (T3SSs). Strikingly, EBs orient with their T3SS-containing pole facing target cells, enabling the T3SSs to directly contact the cellular plasma membrane. This contact induces enveloping macropinosomes, actin-rich filopodia and phagocytic cups to zipper tightly around the internalising bacteria. Once encapsulated into tight early vacuoles, EB polarity and the T3SSs are lost. Our findings reveal previously undescribed structural transitions in both pathogen and host during the initial steps of chlamydial invasion.


    Item Type: Article
    Keyword(s) / Subject(s): Chlamydia, electron tomography, host-pathogen interactions, type III secretion
    School: Birkbeck Schools and Departments > School of Science > Biological Sciences
    Research Centre: Structural Molecular Biology, Institute of (ISMB)
    Depositing User: Administrator
    Date Deposited: 12 May 2014 11:44
    Last Modified: 06 Dec 2016 11:14


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