PMID:24628810

Citation	'Vogt, SL and Raivio, TL (2014) Hfq reduces envelope stress by controlling expression of envelope-localized proteins and protein complexes in enteropathogenic Escherichia coli. Mol. Microbiol. '
Abstract	Gram-negative bacteria possess several envelope stress responses that detect and respond to damage to this critical cellular compartment. The σ(E) envelope stress response senses the misfolding of outer membrane proteins (OMPs), while the Cpx two-component system is believed to detect the misfolding of periplasmic and inner membrane proteins. Recent studies in several Gram-negative organisms found that deletion of hfq, encoding a small RNA chaperone protein, activates the σ(E) envelope stress response. In this study, we assessed the effects of deleting hfq upon activity of the σ(E) and Cpx responses in non-pathogenic and enteropathogenic (EPEC) strains of Escherichia coli. We found that the σ(E) response was activated in Δhfq mutants of all E. coli strains tested, resulting from the misregulation of OMPs. The Cpx response was activated by loss of hfq in EPEC, but not in E. coli K-12. Cpx pathway activation resulted in part from overexpression of the bundle-forming pilus (BFP) in EPEC Δhfq. We found that Hfq repressed expression of the BFP via PerA, a master regulator of virulence in EPEC. This study shows that Hfq has a more extensive role in regulating the expression of envelope proteins and horizontally-acquired virulence genes in E. coli than previously recognized.
Links	PubMed Online version:10.1111/mmi.12581
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOCB:D3QWY4		GO:0045040: protein import into mitochondrial outer membrane	ECO:0000314:		P		Refer to Figure 3, "Deletion of major OMP's reduces activation of sigma-E envelope stress response"	complete CACAO 9643

References

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