Adaptation of the periplasm to maintain spatial constraints essential for cell envelope processes and cell viability
- Monash University, Australia
- Georgia Institute of Technology, United States
- Imperial College London, United Kingdom
- The University of Auckland, New Zealand
Abstract
The cell envelope of Gram-negative bacteria consists of two membranes surrounding a periplasm and peptidoglycan layer. Molecular machines spanning the cell envelope depend on spatial constraints and load-bearing forces across the cell envelope and surface. The mechanisms dictating spatial constraints across the cell envelope remain incompletely defined. In Escherichia coli, the coiled-coil lipoprotein Lpp contributes the only covalent linkage between the outer membrane and the underlying peptidoglycan layer. Using proteomics, molecular dynamics and a synthetic lethal screen we show that lengthening Lpp to the upper limit does not change the spatial constraint, but is accommodated by other factors which thereby become essential for viability. Our findings demonstrate E. coli expressing elongated Lpp does not simply enlarge the periplasm in response, but the bacteria accommodate by a combination of tilting Lpp and reducing the amount of the covalent bridge. By genetic screening we identified all of the genes in E. coli that become essential in order to enact this adaptation, and by quantitative proteomics discovered that very few proteins need to be up- or down-regulated in steady-state levels in order to accommodate the longer Lpp. We observed increased levels of factors determining cell stiffness, a decrease in membrane integrity, an increase membrane vesiculation and a dependance on otherwise non-essential tethers to maintain lipid transport and peptidoglycan biosynthesis. Further this has implications for understanding how spatial constraint across the envelope controls processes such as flagellum-driven motility, cellular signaling and protein translocation.
Data availability
All data generated from this study is supplied in the relevant supplemental files
Article and author information
Author details
Christopher J Stubenrauch
Von Vergel L Torres
Funding
Australian Research Council (FL130100038)
- Trevor Lithgow
- Iain D Hay
United States National Institute of Health (R01-GM123169)
- James C Gumbart
United States National Institute of Health (R01-AI052293)
- James C Gumbart
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2022, Mandela 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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Adaptation of the periplasm to maintain spatial constraints essential for cell envelope processes and cell viability
eLife 11:e73516.
https://doi.org/10.7554/eLife.73516
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