This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Murata, T.
Right arrow Articles by Nikaido, H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Murata, T.
Right arrow Articles by Nikaido, H.

 Previous Article  |  Next Article 

Journal of Bacteriology, October 2007, p. 7213-7222, Vol. 189, No. 20
0021-9193/07/$08.00+0     doi:10.1128/JB.00973-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

PhoPQ-Mediated Regulation Produces a More Robust Permeability Barrier in the Outer Membrane of Salmonella enterica Serovar Typhimurium{triangledown}

Takeshi Murata,1 Will Tseng,1 Tina Guina,2,{dagger} Samuel I. Miller,2 and Hiroshi Nikaido1*

Department of Molecular and Cell Biology, University of California, Berkeley, California,1 Department of Microbiology, University of Washington, Seattle, Washington2

Received 19 June 2007/ Accepted 27 July 2007

The PhoPQ two-component system of Salmonella enterica serovar Typhimurium produces a remodeling of the lipid A domain of the lipopolysaccharide, including the PagP-catalyzed addition of palmitoyl residue, the PmrAB-regulated addition of the cationic sugar 4-aminoarabinose and phosphoethanolamine, and the LpxO-catalyzed addition of a 2-OH group onto one of the fatty acids. By using the diffusion rates of the dyes ethidium, Nile red, and eosin Y across the outer membrane, as well as the susceptibility of cells to large, lipophilic agents, we evaluated the function of this membrane as a permeability barrier. We found that the remodeling process in PhoP-constitutive strains produces an outer membrane that serves as a very effective permeability barrier in an environment that is poor in divalent cations or that contains cationic peptides, whereas its absence in phoP null mutants produces an outer membrane severely compromised in its barrier function under these conditions. Removing combinations of the lipid A-remodeling functions from a PhoP-constitutive strain showed that the known modification reactions explain a major part of the PhoPQ-regulated changes in permeability. We believe that the increased barrier property of the remodeled bilayer is important in making the pathogen more resistant to the stresses that it encounters in the host, including attack by the cationic antimicrobial peptides. On the other hand, drug-induced killing assays suggest that the outer membrane containing unmodified lipid A may serve as a better barrier in the presence of high concentrations (e.g., 5 mM) of Mg2+.

* Corresponding author. Mailing address: Department of Molecular and Cell Biology, 16 Barker Hall, University of California, Berkeley, CA 94720-3202. Phone: (510) 642-2027. Fax: (510) 643-6334. E-mail: nhiroshi{at}berkeley.edu

{triangledown} Published ahead of print on 10 August 2007.

{dagger} Present address: Department of Pediatrics, University of Washington, Seattle, WA.

Journal of Bacteriology, October 2007, p. 7213-7222, Vol. 189, No. 20
0021-9193/07/$08.00+0     doi:10.1128/JB.00973-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Sarnacki, S. H., Marolda, C. L., Noto Llana, M., Giacomodonato, M. N., Valvano, M. A., Cerquetti, M. C. (2009). Dam Methylation Controls O-Antigen Chain Length in Salmonella enterica Serovar Enteritidis by Regulating the Expression of Wzz Protein. J. Bacteriol. 191: 6694-6700 [Abstract] [Full Text]  
  • Bourret, T. J., Song, M., Vazquez-Torres, A. (2009). Codependent and Independent Effects of Nitric Oxide-Mediated Suppression of PhoPQ and Salmonella Pathogenicity Island 2 on Intracellular Salmonella enterica Serovar Typhimurium Survival. Infect. Immun. 77: 5107-5115 [Abstract] [Full Text]  
  • Prieto, A. I., Hernandez, S. B., Cota, I., Pucciarelli, M. G., Orlov, Y., Ramos-Morales, F., Garcia-del Portillo, F., Casadesus, J. (2009). Roles of the Outer Membrane Protein AsmA of Salmonella enterica in the Control of marRAB Expression and Invasion of Epithelial Cells. J. Bacteriol. 191: 3615-3622 [Abstract] [Full Text]  
  • Malinverni, J. C., Silhavy, T. J. (2009). An ABC transport system that maintains lipid asymmetry in the Gram-negative outer membrane. Proc. Natl. Acad. Sci. USA 106: 8009-8014 [Abstract] [Full Text]  
  • Goldman, S. R., Tu, Y., Goldberg, M. B. (2008). Differential Regulation by Magnesium of the Two MsbB Paralogs of Shigella flexneri. J. Bacteriol. 190: 3526-3537 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»