All Publications


  • Mechanical stress compromises multicomponent efflux complexes in bacteria PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Genova, L. A., Roberts, M. F., Wong, Y., Harper, C. E., Santiago, A., Fu, B., Srivastava, A., Jung, W., Wang, L. M., Krzeminski, L., Mao, X., Sun, X., Hui, C., Chen, P., Hernandez, C. J. 2019; 116 (51): 25462–67

    Abstract

    Physical forces have a profound effect on growth, morphology, locomotion, and survival of organisms. At the level of individual cells, the role of mechanical forces is well recognized in eukaryotic physiology, but much less is known about prokaryotic organisms. Recent findings suggest an effect of physical forces on bacterial shape, cell division, motility, virulence, and biofilm initiation, but it remains unclear how mechanical forces applied to a bacterium are translated at the molecular level. In Gram-negative bacteria, multicomponent protein complexes can form rigid links across the cell envelope and are therefore subject to physical forces experienced by the cell. Here we manipulate tensile and shear mechanical stress in the bacterial cell envelope and use single-molecule tracking to show that octahedral shear (but not hydrostatic) stress within the cell envelope promotes disassembly of the tripartite efflux complex CusCBA, a system used by Escherichia coli to resist copper and silver toxicity. By promoting disassembly of this protein complex, mechanical forces within the cell envelope make the bacteria more susceptible to metal toxicity. These findings demonstrate that mechanical forces can inhibit the function of cell envelope protein assemblies in bacteria and suggest the possibility that other multicomponent, transenvelope efflux complexes may be sensitive to mechanical forces including complexes involved in antibiotic resistance, cell division, and translocation of outer membrane components. By modulating the function of proteins within the cell envelope, mechanical stress has the potential to regulate multiple processes required for bacterial survival and growth.

    View details for DOI 10.1073/pnas.1909562116

    View details for Web of Science ID 000503281500023

    View details for PubMedID 31772020

    View details for PubMedCentralID PMC6925999

  • Viscoelasticity of the axon limits stretch-mediated growth COMPUTATIONAL MECHANICS Wang, L. M., Kuhl, E. 2019