HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Reiling, S. A. Articles by Rowen, D. W. Search for Related Content PubMed PubMed Citation Articles by Reiling, S. A. Articles by Rowen, D. W. Agricola Articles by Reiling, S. A. Articles by Rowen, D. W.

Prc protease promotes mucoidy in mucA mutants of Pseudomonas aeruginosa

Department of Biology, University of Nebraska at Omaha, Omaha, NE 68182, USA

Correspondence
D. W. Rowen
drowen{at}mail.unomaha.edu

Mucoid strains of Pseudomonas aeruginosa that overproduce the exopolysaccharide alginate are a frequent cause of chronic respiratory infections in cystic fibrosis (CF) patients. The overproduction of alginate by these strains is often caused by mutations within mucA of the algU mucABCD gene cluster. This gene cluster encodes an extreme stress response system composed of the ECF alternative sigma factor AlgU, the anti-sigma factor MucA located in the inner membrane and the negative regulator MucB located in the periplasm. Most of the mutations in mucA found in mucoid strains cause a truncation of the C-terminal, periplasmic domain of MucA. The most significant effect of these mutations appears to be to reduce the levels of MucA. PA3257 (prc) was identified as a regulator of alginate production in P. aeruginosa through the isolation and study of mutations that partially suppressed the mucoid phenotype of a mucA22 strain. The suppressor of mucoidy (som) mutants isolated produced very little alginate when grown on LB medium, but were still mucoid when grown on Pseudomonas isolation agar. These som mutations and another previously isolated suppressor mutation were complemented by cosmids or plasmids carrying PA3257. PA3257 is predicted to encode a periplasmic protease similar to Prc or Tsp of Escherichia coli. Sequencing of prc from three strains with som suppressor mutations confirmed that each had a mutation within the prc coding region. The authors propose that Prc acts to degrade mutant forms of MucA. Additional evidence in support of this hypothesis is: (1) transcription from the AlgU-regulated algD reporter was reduced in som mutants; (2) inactivation of prc affected alginate production in mucoid strains with other mucA mutations found in CF isolates; (3) inactivation or overexpression of prc did not affect alginate production in strains with wild-type MucA.

This article has been cited by other articles:

				D. Qiu, V. M. Eisinger, D. W. Rowen, and H. D. Yu Regulated proteolysis controls mucoid conversion in Pseudomonas aeruginosa PNAS, May 8, 2007; 104(19): 8107 - 8112. [Abstract] [Full Text] [PDF]

				R. Chaba, I. L. Grigorova, J. M. Flynn, T. A. Baker, and C. A. Gross Design principles of the proteolytic cascade governing the {sigma}E-mediated envelope stress response in Escherichia coli: keys to graded, buffered, and rapid signal transduction Genes & Dev., January 1, 2007; 21(1): 124 - 136. [Abstract] [Full Text] [PDF]