Cell wall synthesis is necessary for membrane dynamics during sporulation of Bacillus subtilis

Authors

  • Pablo Meyer,

    1. Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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  • Jennifer Gutierrez,

    1. Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093, USA.
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  • Kit Pogliano,

    1. Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093, USA.
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  • Jonathan Dworkin

    Corresponding author
    1. Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
      E-mail jonathan.dworkin@columbia.edu; Tel. (+1) 212 342 3731; Fax (+1) 212 305 1468.
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E-mail jonathan.dworkin@columbia.edu; Tel. (+1) 212 342 3731; Fax (+1) 212 305 1468.

Summary

During Bacillus subtilis sporulation, an endocytic-like process called engulfment results in one cell being entirely encased in the cytoplasm of another cell. The driving force underlying this process of membrane movement has remained unclear, although components of the machinery have been characterized. Here we provide evidence that synthesis of peptidoglycan, the rigid, strength bearing extracellular polymer of bacteria, is a key part of the missing force-generating mechanism for engulfment. We observed that sites of peptidoglycan synthesis initially coincide with the engulfing membrane and later with the site of engulfment membrane fission. Furthermore, compounds that block muropeptide synthesis or polymerization prevented membrane migration in cells lacking a component of the engulfment machinery (SpoIIQ), and blocked the membrane fission event at the completion of engulfment in all cells. In addition, these compounds inhibited bulge and vesicle formation that occur in spoIID mutant cells unable to initiate engulfment, as did genetic ablation of a protein that polymerizes muropeptides. This is the first report to our knowledge that peptidoglycan synthesis is necessary for membrane movements in bacterial cells and has implications for the mechanism of force generation during cytokinesis.

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