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Mechanical strain sensing implicated in cell shape recovery in Escherichia coli

Nature Microbiology volume 2, Article number: 17115 (2017) Cite this article

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Abstract

The shapes of most bacteria are imparted by the structures of their peptidoglycan cell walls, which are determined by many dynamic processes that can be described on various length scales ranging from short-range glycan insertions to cellular-scale elasticity1–11. Understanding the mechanisms that maintain stable, rod-like morphologies in certain bacteria has proved to be challenging due to an incomplete understanding of the feedback between growth and the elastic and geometric properties of the cell wall3,4,12–14. Here, we probe the effects of mechanical strain on cell shape by modelling the mechanical strains caused by bending and differential growth of the cell wall. We show that the spatial coupling of growth to regions of high mechanical strain can explain the plastic response of cells to bending4 and quantitatively predict the rate at which bent cells straighten. By growing filamentous Escherichia coli cells in doughnut-shaped microchambers, we find that the cells recovered their straight, native rod-shaped morphologies when released from captivity at a rate consistent with the theoretical prediction. We then measure the localization of MreB, an actin homologue crucial to cell wall synthesis, inside confinement and during the straightening process, and find that it cannot explain the plastic response to bending or the observed straightening rate. Our results implicate mechanical strain sensing, implemented by components of the elongasome yet to be fully characterized, as an important component of robust shape regulation in E. coli.

Cell shape, which in many types of bacteria is determined by a mechanically rigid peptidoglycan (PG) cell wall, is crucial for bacterial motility, proliferation, adhesion and survival1–3. Rod-like bacteria maintain their shapes at a fixed diameter with extraordinary precision during growth, and elongate by the action of the peptidoglycan elongation machinery (PGEM), a multi-enzyme complex consisting of penicillin-binding proteins (PBPs) and conserved membrane proteins (MreC, MreD, RodA, RodZ and other shape, elongation, division, sporulation (SEDS) family proteins)5,6,15,16. Recent experimental studies have led to a qualitative description of cell wall growth on a molecular level: the PGEM interacts with the actin homologue MreB to direct the local, circumferential insertion of new glycan strands into the existing PG structure. Although the general roles of PGEM enzymes in cell wall elongation are well studied5–9,17, the feedback mechanism between cell shape—as determined by the geometric and elastic properties of the cell wall—and PGEM-related subcellular components is not understood. It is unclear whether the mechanisms needed to maintain robust cellular morphology detect cellular geometry12,18 or mechanical stresses3,4,13,14.

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Figure 1: Three theories for cellular shape regulation.
Figure 2: Areal strain-dependent PG elongation quantitatively predicts shape recovery dynamics.
Figure 3: Quantitative analysis of cellular straightening dynamics.
Figure 4: MreB–msfGFP fusion cells exhibit MreB enrichment at negative Gaussian curvature, but MreB enrichment alone cannot explain straightening.

References

  1. Cabeen, M. T. & Jacobs-Wagner, C. Bacterial cell shape. Nat. Rev. Microbiol. 3, 601–610 (2005).

    Article  CAS  PubMed  Google Scholar 

  2. Young, K. D. The selective value of bacterial shape. Microbiol. Mol. Biol. Rev. 70, 660–703 (2006).

    Article  PubMed  PubMed Central  Google Scholar 

  3. Amir, A. & van Teeffelen, S. Getting into shape: how do rod-like bacteria control their geometry? Syst. Synth. Biol. 8, 227–235 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  4. Amir, A., Babaeipour, F., McIntosh, D. B., Nelson, D. R. & Jun, S. Bending forces plastically deform growing bacterial cell walls. Proc. Natl Acad. Sci. USA 111, 5778–5783 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Garner, E. C. et al. Coupled, circumferential motions of the cell wall synthesis machinery and MreB filaments in B. subtilis. Science 333, 222–225 (2011).

    CAS  PubMed  Google Scholar 

  6. Domínguez-Escobar, J. et al. Processive movement of MreB-associated cell wall biosynthetic complexes in bacteria. Science 333, 225–228 (2011).

    Article  PubMed  Google Scholar 

  7. Lee, T. K. et al. A dynamically assembled cell wall synthesis machinery buffers cell growth. Proc. Natl Acad. Sci. USA 111, 4554–4559 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  8. Paradis-Bleau, C. et al. Lipoprotein cofactors located in the outer membrane activate bacterial cell wall polymerases. Cell 143, 1110–1120 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  9. Typas, A. et al. Regulation of peptidoglycan synthesis by outer-membrane proteins. Cell 143, 1097–1109 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  10. Reshes, G., Vanounou, S., Fishov, I. & Feingold, M. Cell shape dynamics in Escherichia coli. Biophys. J. 94, 251–264 (2008).

    Article  CAS  PubMed  Google Scholar 

  11. Bartlett, T. M. et al. A periplasmic polymer curves Vibrio cholerae and promotes pathogenesis. Cell 168, 172–185 (2017).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  12. Ursell, T. S. et al. Rod-like bacterial shape is maintained by feedback between cell curvature and cytoskeletal localization. Proc. Natl Acad. Sci. USA 111, 1025–1034 (2014).

    Article  Google Scholar 

  13. Amir, A. & Nelson, D. R. Dislocation-mediated growth of bacterial cell walls. Proc. Natl Acad. Sci. USA 109, 9833–9838 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  14. Si, F., Li, B. & Sun, S. X. Bacterial growth and shape regulation by external compression. Sci. Rep. 5, 11367 (2015).

    Article  PubMed  PubMed Central  Google Scholar 

  15. Meeske, A. J. et al. SEDS proteins are a widespread family of bacterial cell wall polymerases. Nature 537, 634–638 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  16. Cho, H. et al. Bacterial cell wall biogenesis is mediated by SEDS and PBP polymerase families functioning semi-autonomously. Nat. Microbiol. 1, 16172 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  17. Nguyen, L. T., Gumbart, J. C., Beeby, M. & Jensen, G. J. Coarse-grained simulations of bacterial cell wall growth reveal that local coordination alone can be sufficient to maintain rod shape. Proc. Natl Acad. Sci. USA 112, E3689–E3698 (2015).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Renner, L. D., Eswaramoorthy, P., Ramamurthi, K. S. & Weibel, D. B. Studying biomolecule localization by engineering bacterial cell wall curvature. PLoS ONE 8, e84143 (2013).

    Article  PubMed  PubMed Central  Google Scholar 

  19. Caspi, Y. Deformation of filamentous Escherichia coli cells in a microfluidic device: a new technique to study cell mechanics. PLoS ONE 9, e83775 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  20. Takeuchi, S., DiLuzio, W. R., Weibel, D. B. & Whitesides, G. M. Controlling the shape of filamentous cells of Escherichia coli. Nano Lett. 5, 1819–1823 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  21. Mannik, J., Driessen, R., Galajda, P., Keymer, J. E. & Dekker, C. Bacterial growth and motility in sub-micron constrictions. Proc. Natl Acad. Sci. USA 106, 14861–14866 (2009).

    Article  PubMed  PubMed Central  Google Scholar 

  22. Cabeen, M. T. et al. Bacterial cell curvature through mechanical control of growth. EMBO J. 28, 1208–1219 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. Sliusarenko, O., Cabeen, M. T., Wolgemuth, C. W., Jacobs-Wagner, C. & Emonet, T. Processivity of peptidoglycan synthesis provides a built-in mechanism for the robustness of straight-rod cell morphology. Proc. Natl Acad. Sci. USA 107, 10086–10091 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Mukhopadhyay, R. & Wingreen, N. S. Curvature and shape determination of growing bacteria. Phys. Rev. E 80, 062901 (2009).

    Article  Google Scholar 

  25. Rojas, E., Theriot, J. A. & Huang, K. C. Response of Escherichia coli growth rate to osmotic shock. Proc. Natl Acad. Sci. USA 111, 7807–7812 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Wang, S., Furchtgott, L., Huang, K. C. & Shaevitz, J. W. Helical insertion of peptidoglycan produces chiral ordering of the bacterial cell wall. Proc. Natl Acad. Sci. USA 109, 595–604 (2012).

    Article  Google Scholar 

  27. van Teeffelen, S. et al. The bacterial actin MreB rotates, and rotation depends on cell-wall assembly. Proc. Natl Acad. Sci. USA 108, 15822–15827 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  28. Harris, L. K., Dye, N. A. & Theriot, J. A. A Caulobacter MreB mutant with irregular cell shape exhibits compensatory widening to maintain a preferred surface area to volume ratio. Mol. Microbiol. 94, 988–1005 (2014).

    Article  CAS  Google Scholar 

  29. Kim, S. Y., Gitai, Z., Kinkhabwala, A., Shapiro, L. & Moerner, W. E. Single molecules of the bacterial actin MreN undergo directed treadmilling motion in Caulobacter crescentus. Proc. Natl Acad. Sci. USA 103, 10929–10934 (2006).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  30. Tuson, H. H. et al. Measuring the stiffness of bacterial cells from growth rates in hydrogels of tunable elasticity. Mol. Microbiol. 85, 874–891 (2012).

    Article  Google Scholar 

  31. Stewart, E. J., Madden, R., Paul, G. & Taddei, F. Aging and death in an organism that reproduces by morphologically symmetric division. PLoS Biol. 3, e45 (2005).

    Article  PubMed  PubMed Central  Google Scholar 

  32. Ouzounov, N. et al. MreB orientation correlates with cell diameter in Escherichia coli. Biophys. J. 111, 1035–1043 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  33. Paradis-Bleau, C. et al. Lipoprotein cofactors located in the outer membrane activate bacterial cell wall polymerases. Cell 143, 1110–1120 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  34. Egan, A. J. F. et al. Outer-membrane lipoprotein LpoB spans the periplasm to stimulate the peptidoglycan synthase PBP1B. Proc. Natl Acad. Sci. USA 111, 8197–8202 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  35. Lee, T. K., Meng, K., Shi, H. & Huang, K. C. Single-molecule imaging reveals modulation of cell wall synthesis dynamics in live bacterial cells. Nat. Commun. 7, 13170 (2016).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Efrati, E., Sharon, E. & Kupferman, R. The metric description of elasticity in residually stressed soft materials. Soft Matter 9, 8187–8197 (2013).

    Article  Google Scholar 

  37. Santangelo, C. D. Buckling thin disks and ribbons with non-Euclidean metrics. EPL 86, 34003 (2009).

    Article  Google Scholar 

  38. Weibel, D. B., Diluzio, W. R. & Whitesides, G. M. Microfabrication meets microbiology. Nat. Rev. Microbiol. 5, 209–218 (2007).

    Article  CAS  PubMed  Google Scholar 

  39. Renner, L. D. & Weibel, D. B. Cardiolipin microdomains localize to negatively curved regions of Escherichia coli membranes. Proc. Natl Acad. Sci. USA 108, 6264–6269 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  40. Xia, Y. & Whitesides, G. M. Soft lithography. Angew. Chem. Int. Ed. 37, 550–575 (1998).

    Article  CAS  Google Scholar 

  41. Huang, J., Cao, C. & Lutkenhaus, J. Interaction between FtsZ and inhibitors of cell division. J. Bacteriol. 178, 5080–5085 (1996).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  42. Huisman, O., D'Ari, R. & Gottesman, S. Cell-division control in Escherichia coli: specific induction of the SOS function SfiA protein is sufficient to block septation. Proc. Natl Acad. Sci. USA 81, 4490–4494 (1984).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Bertani, G. Studies on lysogenesis. I. The mode of phage liberation by lysogenic Escherichia coli. J. Bacteriol. 62, 293–300 (1951).

    CAS  PubMed  PubMed Central  Google Scholar 

  44. Bertani, G. Lysogeny at mid-twentieth century: P1, P2, and other experimental systems. J. Bacteriol. 186, 595–600 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  45. Miller, J. H. Experiments in Molecular Genetics (Cold Spring Harbor, 1972).

    Google Scholar 

  46. Sliusarenko, O., Heinritz, J., Emonet, T. & Jacobs-Wagner, C. High-throughput, subpixel precision analysis of bacterial morphogenesis and intracellular spatio-temporal dynamics. Mol. Microbiol. 80, 612–627 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

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Acknowledgements

F.W. was supported by the National Science Foundation Graduate Research Fellowship under grant no. DGE1144152. L.D.R., S.v.T. and A.A. were supported by the Volkswagen Foundation. G.O. and S.v.T. were supported by funds from the European Research Council (ERC-2015-STG RCSB 679980), the LabEx IBEID (Integrative Biology of Emerging Infectious Diseases) programme, the Mairie de Paris ‘Emergence(s)’ programme, and the ANR ‘Investissement d'Avenir Programme’ (10-LABX-62-IBEID) to S.v.T. J.P. acknowledges funding by a Delta ITP Zwaartekracht grant. A.A. was supported by the Alfred P. Sloan Foundation. The authors thank J. Hutchinson for discussions on shell theory, J. Hutchinson, E.C. Garner and C. Wivagg for comments on the manuscript, L. Mahadevan and C. Wivagg for discussions on the model, K. Bertoldi and J. Liu for help with simulation software, E. Oldewurtel and E. Brambilla for help with microscopy and N. Ouzounov for providing the MreB-msfGFP strain.

Author information

Author notes

  1. Felix Wong and Lars D. Renner: These authors contributed equally to this work.

Authors and Affiliations

  1. School of Engineering and Applied Sciences, Harvard University, Cambridge, 02138, Massachusetts, USA

    Felix Wong & Ariel Amir

  2. Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, 01069 Dresden, Germany

    Lars D. Renner

  3. Department of Biochemistry, University of Wisconsin-Madison, Madison, 53706, Wisconsin, USA

    Lars D. Renner & Douglas B. Weibel

  4. Department of Microbiology, Institut Pasteur, 75724 Paris, France

    Gizem Özbaykal & Sven van Teeffelen

  5. Departments of Physics and Integrative Biology, University of California, Berkeley, 94720, California, USA

    Jayson Paulose

  6. Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, 53706, Wisconsin, USA

    Douglas B. Weibel

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Contributions

F.W. and A.A. developed the model of straightening. F.W. and J.P. performed simulations. L.D.R., G.Ö., D.B.W., S.v.T. and A.A. designed the experiments. L.D.R. and G.Ö. performed the experiments. F.W., L.D.R. and G.Ö. analysed the data. F.W. and G.Ö. wrote cell-tracking software. F.W., L.D.R., G.Ö., S.v.T. and A.A. wrote the paper.

Corresponding authors

Correspondence to Lars D. Renner or Ariel Amir.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Notes 1 and 2, Supplementary Discussion, Supplementary Methods, Supplementary References, Supplementary Tables 1 and 2, Supplementary Figures 1–11. (PDF 14721 kb)

Supplementary Video 1

Straightening dynamics of single E. coli cells. Supplementary Videos 1–10 show individual, filamentous E. coli cells recovering their native rod shapes as they grow after release from toroidal microchambers. The time between frames is 2 minutes, the time lapses cover a period of around 40 minutes, and the field of view is approximately 40 μm wide. (MOV 73 kb)

Supplementary Video 2

Straightening dynamics of single E. coli cells. (MOV 58 kb)

Supplementary Video 3

Straightening dynamics of single E. coli cells. (MOV 63 kb)

Supplementary Video 4

Straightening dynamics of single E. coli cells. (MOV 34 kb)

Supplementary Video 5

Straightening dynamics of single E. coli cells. (MOV 123 kb)

Supplementary Video 6

Straightening dynamics of single E. coli cells. (MOV 92 kb)

Supplementary Video 7

Straightening dynamics of single E. coli cells. (MOV 52 kb)

Supplementary Video 8

Straightening dynamics of single E. coli cells. (MOV 94 kb)

Supplementary Video 9

Straightening dynamics of single E. coli cells. (MOV 72 kb)

Supplementary Video 10

Straightening dynamics of single E. coli cells. (MOV 20 kb)

Supplementary Video 11

Numerical simulation of the growth process. Numerical simulations in (1) the case of zero processivity; (2) the case of infinite processivity; and (3) the case of a self-consistent areal strain coupling that results in a constant differential growth in phase 1 and straightening in phase 2. The simulation methodology is detailed in the Supplementary Methods. (MP4 5860 kb)

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Wong, F., Renner, L., Özbaykal, G. et al. Mechanical strain sensing implicated in cell shape recovery in Escherichia coli. Nat Microbiol 2, 17115 (2017). https://doi.org/10.1038/nmicrobiol.2017.115

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