Inter-membrane association of the Sec and BAM translocons for bacterial outer-membrane biogenesis

  1. Sara Alvira
  2. Daniel W Watkins
  3. Luca A Troman
  4. William J Allen
  5. James Stuart Lorriman
  6. Gianluca Degliesposti
  7. Eli J Cohen
  8. Morgan Beeby
  9. Bertram Daum
  10. Vicki AM Gold
  11. J Mark Skehel
  12. Ian Collinson  Is a corresponding author
  1. University of Bristol, United Kingdom
  2. Francis Crick Institute, United Kingdom
  3. Imperial College London, United Kingdom
  4. University of Exeter, United Kingdom

Abstract

The outer-membrane of Gram-negative bacteria is critical for surface adhesion, pathogenicity, antibiotic resistance and survival. The major constituent – hydrophobic b-barrel Outer-Membrane Proteins (OMPs) – are first secreted across the inner-membrane through the Sec-translocon for delivery to periplasmic chaperones e.g. SurA, which prevent aggregation. OMPs are then offloaded to the b-Barrel Assembly Machinery (BAM) in the outer-membrane for insertion and folding. We show the Holo-TransLocon (HTL) – an assembly of the protein-channel core-complex SecYEG, the ancillary sub-complex SecDF, and the membrane 'insertase' YidC – contacts BAM through periplasmic domains of SecDF and YidC, ensuring efficient OMP maturation. Furthermore, the proton-motive-force (PMF) across the inner-membrane acts at distinct stages of protein secretion: (1) SecA-driven translocation through SecYEG; and (2) communication of conformational changes via SecDF across the periplasm to BAM. The latter presumably drives efficient passage of OMPs. These interactions provide insights of inter-membrane organisation and communication, the importance of which is becoming increasingly apparent.

Data availability

All data generated or analysed during this study are included in the manuscript and supplementary information. Information regarding statistical testing is located in materials and methods and corresponding figure legends.

Article and author information

Author details

  1. Sara Alvira

    School of Biochemistry, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  2. Daniel W Watkins

    School of Biochemistry, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3825-5036
  3. Luca A Troman

    School of Biochemistry, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  4. William J Allen

    School of Biochemistry, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9513-4786
  5. James Stuart Lorriman

    School of Biochemistry, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1755-0805
  6. Gianluca Degliesposti

    Mass Spectrometry science technology platform, Francis Crick Institute, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  7. Eli J Cohen

    Department of Life Sciences, Imperial College London, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  8. Morgan Beeby

    Department of Life Sciencesa, Imperial College London, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6413-9835
  9. Bertram Daum

    Living Systems Institute, University of Exeter, Frankfurt, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3767-264X
  10. Vicki AM Gold

    Living Systems Institute, University of Exeter, Exeter, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6908-0745
  11. J Mark Skehel

    Mass Spectrometry science technology platform, Francis Crick Institute, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  12. Ian Collinson

    School of Biochemistry, University of Bristol, Bristol, United Kingdom
    For correspondence
    ian.collinson@bristol.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3931-0503

Funding

Biotechnology and Biological Sciences Research Council (BB/S008349/1)

  • Sara Alvira

EMBO (LTFCOFUND2013)

  • Sara Alvira

EMBO (GA-2013-609409)

  • Sara Alvira

Biotechnology and Biological Sciences Research Council (BB/S008349/1)

  • Daniel W Watkins

Biotechnology and Biological Sciences Research Council (BB/S008349/1)

  • Ian Collinson

Biotechnology and Biological Sciences Research Council (BB/N015126/1)

  • Ian Collinson

Biotechnology and Biological Sciences Research Council (BB/N015126/1)

  • Daniel W Watkins

Biotechnology and Biological Sciences Research Council (BB/M003604/1)

  • Ian Collinson

Biotechnology and Biological Sciences Research Council (BB/M003604/1)

  • Sara Alvira

Biotechnology and Biological Sciences Research Council (BB/J014400/1)

  • Luca A Troman

EMBO (ALTF 710-2015)

  • Sara Alvira

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

Reviewing Editor

  1. Volker Dötsch, Goethe University, Germany

Version history

  1. Received: July 2, 2020
  2. Accepted: November 3, 2020
  3. Accepted Manuscript published: November 4, 2020 (version 1)
  4. Version of Record published: November 27, 2020 (version 2)

Copyright

© 2020, Alvira 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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  1. Sara Alvira
  2. Daniel W Watkins
  3. Luca A Troman
  4. William J Allen
  5. James Stuart Lorriman
  6. Gianluca Degliesposti
  7. Eli J Cohen
  8. Morgan Beeby
  9. Bertram Daum
  10. Vicki AM Gold
  11. J Mark Skehel
  12. Ian Collinson
(2020)
Inter-membrane association of the Sec and BAM translocons for bacterial outer-membrane biogenesis
eLife 9:e60669.
https://doi.org/10.7554/eLife.60669

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https://doi.org/10.7554/eLife.60669

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