Inter-membrane association of the Sec and BAM translocons for bacterial outer-membrane biogenesis
- University of Bristol, United Kingdom
- Francis Crick Institute, United Kingdom
- Imperial College London, United Kingdom
- 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
James Stuart Lorriman
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
- Volker Dötsch, Goethe University, Germany
Version history
- Received: July 2, 2020
- Accepted: November 3, 2020
- Accepted Manuscript published: November 4, 2020 (version 1)
- 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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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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