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Different roles for anti-sigma factors in siderophore signalling pathways of Pseudomonas aeruginosa


Mettrick, KA and Lamont, IL, Different roles for anti-sigma factors in siderophore signalling pathways of Pseudomonas aeruginosa, Molecular Microbiology, 74, (5) pp. 1257-1271. ISSN 0950-382X (2009) [Refereed Article]

DOI: doi:10.1111/j.1365-2958.2009.06932.x


Group IV (extracytoplasmic function) sigma factors direct the expression of a large number of regulons in bacteria. The activities of many Group IV sigma factors are inhibited by members of a family of anti-sigma factor proteins, with appropriate environmental signals causing the sigma factor to be released for interaction with core RNA polymerase and consequent transcription of target genes. One subgroup of Group IV sigmas directs expression of genes for uptake of siderophores (iron-chelating compounds) by Gram-negative bacteria. The activities of these sigma factors are controlled by anti-sigma factors that span the cytoplasmic membrane. Binding of siderophore by a receptor protein in the outer membrane results in signal transduction from the periplasmic portion to the cytoplasmic portion of the appropriate anti-sigma factor, with consequent activity of the cognate sigma factor and upregulation of the gene encoding the receptor protein. We have investigated receptor/anti-sigma/sigma factor signalling pathways for uptake of the siderophores ferrichrome and desferrioxamine by Pseudomonas aeruginosa. In these pathways the 'anti-sigma' proteins are normally required for sigma factor activity and the cytoplasmic parts of the 'anti-sigmas' have 'pro-sigma' activity. We suggest that the family of anti-sigma factor proteins may be better considered as 'sigma regulators'. © 2009 Blackwell Publishing Ltd.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Microbiology
Research Field:Bacteriology
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Mettrick, KA (Dr Karla Mettrick)
ID Code:63722
Year Published:2009
Web of Science® Times Cited:41
Deposited By:Menzies Institute for Medical Research
Deposited On:2010-05-26
Last Modified:2010-05-26

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