1. Microbiology and Infectious Disease
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Visualization of the type III secretion mediated Salmonella-host cell interface using cryo-electron tomography

  1. Donghyun Park
  2. Maria Lara-Tejero
  3. M Neal Waxham
  4. Wenwei Li
  5. Bo Hu
  6. Jorge E Galán
  7. Jun Liu  Is a corresponding author
  1. Yale University School of Medicine, United States
  2. The University of Texas Health Science Center at Houston, United States
Research Article
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Cite this article as: eLife 2018;7:e39514 doi: 10.7554/eLife.39514

Abstract

Many important gram-negative bacterial pathogens use highly sophisticated type III protein secretion systems (T3SSs) to establish complex host-pathogen interactions. Bacterial-host cell contact triggers the activation of the T3SS and the subsequent insertion of a translocon pore into the target cell membrane, which serves as a conduit for the passage of effector proteins. Therefore the initial interaction between T3SS-bearing bacteria and host cells is the critical step in the deployment of the protein secretion machine, yet this process remains poorly understood. Here, we use high-throughput cryo-electron tomography (cryo-ET) to visualize the T3SS-mediated Salmonella-host cell interface. Our analysis reveals the intact translocon at an unprecedented level of resolution, its deployment in the host cell membrane, and the establishment of an intimate association between the bacteria and the target cells, which is essential for effector translocation. Our studies provide critical data supporting the long postulated direct injection model for effector translocation.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files.

Article and author information

Author details

  1. Donghyun Park

    Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-2048-6004
  2. Maria Lara-Tejero

    Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. M Neal Waxham

    Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Wenwei Li

    Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Bo Hu

    Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Jorge E Galán

    Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6531-0355
  7. Jun Liu

    Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States
    For correspondence
    jliu@yale.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3108-6735

Funding

National Institute of Allergy and Infectious Diseases (AI030492)

  • Jorge E Galán

National Institute of General Medical Sciences (GM107629)

  • Jun Liu

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Kim Orth, HHMI/University of Texas Southwestern Medical Center, United States

Publication history

  1. Received: June 25, 2018
  2. Accepted: September 24, 2018
  3. Accepted Manuscript published: October 3, 2018 (version 1)
  4. Version of Record published: October 8, 2018 (version 2)

Copyright

© 2018, Park et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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