title: Glutathione activates virulence gene expression of an intracellular pathogen.
abstract: Intracellular pathogens are responsible for much of the world-wide morbidity and mortality due to infectious diseases. To colonize their hosts successfully, pathogens must sense their environment and regulate virulence gene expression appropriately. Accordingly, on entry into mammalian cells, the facultative intracellular bacterial pathogen Listeria monocytogenes remodels its transcriptional program by activating the master virulence regulator PrfA. Here we show that bacterial and host-derived glutathione are required to activate PrfA. In this study a genetic selection led to the identification of a bacterial mutant in glutathione synthase that exhibited reduced virulence gene expression and was attenuated 150-fold in mice. Genome sequencing of suppressor mutants that arose spontaneously in vivo revealed a single nucleotide change in prfA that locks the protein in the active conformation (PrfA*) and completely bypassed the requirement for glutathione during infection. Biochemical and genetic studies support a model in which glutathione-dependent PrfA activation is mediated by allosteric binding of glutathione to PrfA. Whereas glutathione and other low-molecular-weight thiols have important roles in redox homeostasis in all forms of life, here we demonstrate that glutathione represents a critical signalling molecule that activates the virulence of an intracellular pathogen.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Reniere
authors.affiliation: Graduate Group in Infectious Diseases and Immunity, School of Public Health, University of California, Berkeley, California 94720, USA.
authors.forename: Aaron T
authors.initials: AT
authors.lastname: Whiteley
authors.affiliation: Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, USA.
authors.forename: Keri L
authors.initials: KL
authors.lastname: Hamilton
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA.
authors.forename: Sonya M
authors.initials: SM
authors.lastname: John
authors.affiliation: Aduro BioTech, Inc. Berkeley, California 94710, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Lauer
authors.affiliation: Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, USA.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Brennan
authors.affiliation: 1] Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA [2] School of Public Health, University of California, Berkeley, California 94720, USA.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Portnoy
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D001426:Bacterial Proteins / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000235:genetics*; D005978:Glutathione / Q000378:metabolism* / Q000494:pharmacology; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology*; D008089:Listeria monocytogenes / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity*; D008264:Macrophages / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D010454:Peptide Termination Factors / Q000378:metabolism; D011485:Protein Binding; D012641:Selection, Genetic / Q000235:genetics; D013489:Suppression, Genetic / Q000235:genetics; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D010454:Peptide Termination Factors; C545356:PrfA protein, Listeria monocytogenes; D004247:DNA; D005978:Glutathione