Envelope Stress Responses: An Interconnected Safety Net. Issue 3 (March 2017)

• Record Type: Journal Article
• Authors: Grabowicz, Marcin; Silhavy, Thomas J.
• Is Part Of: Trends in biochemical sciences. Volume 42:Issue 3(2017)
• Page Start: 232
• Page End: 242
• Publication Date: 2017-03
• Subjects: outer membrane -- Cpx -- σE -- sRNA; Biochemistry -- Periodicals; 572
• DOI: 10.1016/j.tibs.2016.10.002
• Languages: English
• ISSNs: 0968-0004

Abstract

Abstract : The Escherichia coli cell envelope is a protective barrier at the frontline of interaction with the environment. Fidelity of envelope biogenesis must be monitored to establish and maintain a contiguous barrier. Indeed, the envelope must also be repaired and modified in response to environmental assaults. Envelope stress responses (ESRs) sense envelope damage or defects and alter the transcriptome to mitigate stress. Here, we review recent insights into the stress-sensing mechanisms of the σ E and Cpx systems and the interaction of these ESRs. Small RNAs (sRNAs) are increasingly prominent regulators of the transcriptional response to stress. These fast-acting regulators also provide avenues for inter-ESR regulation that could be important when cells face multiple contemporaneous stresses, as is the case during infection. Trends: Bacterial cell envelope biogenesis and integrity is continuously monitored by dedicated stress responses. In Escherichia coli, the σ E and Cpx responses maintain homeostasis of the outer membrane and the inner membrane, respectively. A proposed lipid signal for σ E activation has expanded the sensing repertoire of this response. sRNAs have become prominent regulators of stress responses, providing effector functions as well as interfacing with other signal transduction systems. The σ E and Cpx signaling exhibits extensive signaling linkages and appear to be antagonistic, perhaps because the cell prioritizes protecting the energy-generating functions of the inner membrane.