Signal integration by the Cpx-envelope stress system

• Published in: FEMS microbiology letters 2012-01, Vol.326 (1), p.12-22
• Main Authors: Hunke, Sabine, Keller, Rebecca, Müller, Volker S.
• Format: Article
• Language: English
• Subjects: accessory protein; bacterial cell death; Bacterial Proteins - chemistry; Bacterial Proteins - physiology; Bacteriology; Biological and medical sciences; Cell death; Cell Membrane - chemistry; Cell Membrane - metabolism; Cell Membrane - physiology; envelope stress; Fimbriae, Bacterial - genetics; Fimbriae, Bacterial - metabolism; Fundamental and applied biological sciences. Psychology; Gram-Negative Bacteria - pathogenicity; Gram-Negative Bacteria - physiology; Integration; inter‐kingdom signalling; Kinases; Lipids; Membrane Proteins - chemistry; Membrane Proteins - physiology; Metals; Microbiology; Miscellaneous; Perturbation; pH effects; Protein Folding; Protein Kinases - chemistry; Protein Kinases - physiology; Proteins; Signal Transduction; Stress, Physiological; Structure-function relationships; two‐component system signalling; Virulence
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2011.02436.x

Abstract The Cpx-envelope stress system coordinates the expression and assembly of surface structures important for the virulence of Gram-negative pathogenic bacteria. It is comprised of the membrane-anchored sensor kinase CpxA, the cytosolic response regulator CpxR and the accessory protein CpxP. Characteristic of the group of two-component systems, the Cpx system responds to a broad range of stimuli including pH, salt, metals, lipids and misfolded proteins that cause perturbation in the envelope. Moreover, the Cpx system has been linked to inter-kingdom signalling and bacterial cell death. However, although signal specificity has been assumed, for most signals the mechanism of signal integration is not understood. Recent structural and functional studies provide the first insights into how CpxP inhibits CpxA and serves as sensor for misfolded pilus subunits, pH and salt. Here, we summarize and reflect on the current knowledge on signal integration by the Cpx-envelope stress system.