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| The EMBO Journal
(1999) 18, 1730–1737, doi:10.1093/emboj/18.7.1730 |
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| Protection of Escherichia coli cells against extreme turgor by activation of MscS and MscL mechanosensitive channels: identification of genes required for MscS activity |
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| Natalia Levina2, 5, Sabine Tötemeyer3, 5, Neil R. Stokes1, 5, Petra Louis1, Michael A. Jones4 and Ian R. Booth1 |
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1 Department of Molecular and Cell Biology, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK 2 Present address: Biology Department, York University, 4700 Keele Street, North York, Ontario, MB3J 1P3, Canada 3 Present address: Microbial Pathogenesis Unit, International Institute of Cellular and Molecular Pathology, University of Luvain, Medical Faculty, Avenue Hippocrate 76, PO box 74.49, 1200 Brussels, Belgium 4 Present address: Institute for Animal Health, Compton, Newbury, RG20 7NN, UK 5 N.Levina, S.Tötemeyer and N.R.Stokes contributed equally to this work To whom correspondence should be addressed Ian R. Booth, gen118@abdn.ac.uk Received 18 January 1999; Revised 15 February 1999; Accepted 18 February 1999. |
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| Abstract |
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| Mechanosensitive channels are ubiquitous amongst bacterial cells and have been proposed to have major roles in the adaptation to osmotic stress, in particular in the management of transitions from high to low osmolarity environments. Electrophysiological measurements have identified multiple channels in Escherichia coli cells. One gene, mscL, encoding a large conductance channel has previously been described, but null mutants were without well-defined phenotypes. Here, we report the characterization of a new gene family required for MscS function, YggB and KefA, which has enabled a rigorous test of the role of the channels. The channel determined by KefA does not appear to have a major role in managing the transition from high to low osmolarity. In contrast, analysis of mutants of E.coli lacking YggB and MscL shows that mechanosensitive channels are designed to open at a pressure change just below that which would cause cell disruption leading to death. |
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| Keywords: mechanosensitive channels, MscL, MscS, osmoregulation, turgor maintenance |
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