title: General Stress Signaling in the Alphaproteobacteria.
abstract: The Alphaproteobacteria uniquely integrate features of two-component signal transduction and alternative σ factor regulation to control transcription of genes that ensure growth and survival across a range of stress conditions. Research over the past decade has led to the discovery of the key molecular players of this general stress response (GSR) system, including the sigma factor σ(EcfG), its anti-σ factor NepR, and the anti-anti-σ factor PhyR. The central molecular event of GSR activation entails aspartyl phosphorylation of PhyR, which promotes its binding to NepR and thereby releases σ(EcfG) to associate with RNAP and direct transcription. Recent studies are providing a new understanding of complex, multilayered sensory networks that activate and repress this central protein partner switch. This review synthesizes our structural and functional understanding of the core GSR regulatory proteins and highlights emerging data that are defining the systems that regulate GSR transcription in a variety of species.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637; email: scrosson@uchicago.edu.
authors.forename: Aretha
authors.initials: A
authors.lastname: Fiebig
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637; email: scrosson@uchicago.edu.
authors.forename: Julien
authors.initials: J
authors.lastname: Herrou
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637; email: scrosson@uchicago.edu.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Willett
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637; email: scrosson@uchicago.edu.
authors.forename: Sean
authors.initials: S
authors.lastname: Crosson
mesh_terms: D020561:Alphaproteobacteria / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002876:Chromosomes, Bacterial; D015964:Gene Expression Regulation, Bacterial; D015398:Signal Transduction; D013312:Stress, Physiological / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins
keywords: ECF sigma factor; HWE and HisKA_2 kinases; PhyR; partner switch; signal transduction; two-component signaling