title: Characterization of the effect of the histidine kinase CovS on response regulator phosphorylation in group A Streptococcus.
abstract: Two-component gene regulatory systems (TCSs) are a major mechanism by which bacteria respond to environmental stimuli and thus are critical to infectivity. For example, the control of virulence regulator/sensor kinase (CovRS) TCS is central to the virulence of the major human pathogen group A Streptococcus (GAS). Here, we used a combination of quantitative in vivo phosphorylation assays, isoallelic strains that varied by only a single amino acid in CovS, and transcriptome analyses to characterize the impact of CovS on CovR phosphorylation and GAS global gene expression. We discovered that CovS primarily serves to phosphorylate CovR, thereby resulting in the repression of virulence factor-encoding genes. However, a GAS strain selectively deficient in CovS phosphatase activity had a distinct transcriptome relative to that of its parental strain, indicating that both CovS kinase and phosphatase activities influence the CovR phosphorylation status. Surprisingly, compared to a serotype M3 strain, serotype M1 GAS strains had high levels of phosphorylated CovR, low transcript levels of CovR-repressed genes, and strikingly different responses to environmental cues. Moreover, the inactivation of CovS in the serotype M1 background resulted in a greater decrease in phosphorylated CovR levels and a greater increase in the transcript levels of CovR-repressed genes than did CovS inactivation in a serotype M3 strain. These data clarify the influence of CovS on the CovR phosphorylation status and provide insight into why serotype M1 GAS strains have high rates of spontaneous mutations in covS during invasive GAS infection, thus providing a link between TCS molecular function and the epidemiology of deadly bacterial infections.
authors.affiliation: Department of Infectious Diseases, MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Nicola
authors.initials: N
authors.lastname: Horstmann
authors.affiliation: Department of Infectious Diseases, MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Pranoti
authors.initials: P
authors.lastname: Sahasrabhojane
authors.affiliation: Department of Infectious Diseases, MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Miguel
authors.initials: M
authors.lastname: Saldaña
authors.affiliation: Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Nadim J
authors.initials: NJ
authors.lastname: Ajami
authors.affiliation: Department of Pediatrics and Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Flores
authors.affiliation: Department of Microbiology and Immunology, University of Nevada School of Medicine, Reno, Nevada, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Sumby
authors.affiliation: Department of Experimental Therapeutics, MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Chang-Gong
authors.initials: CG
authors.lastname: Liu
authors.affiliation: Department of Bioinformatics and Computational Biology, MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Yao
authors.affiliation: Department of Bioinformatics and Computational Biology, MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Su
authors.affiliation: DNA Sequencing Facility, MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Erika
authors.initials: E
authors.lastname: Thompson
authors.affiliation: Department of Infectious Diseases, MD Anderson Cancer Center, Houston, Texas, USA Department of Genomic Medicine, MD Anderson Cancer Center, Houston, Texas, USA sshelburne@mdanderson.org.
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Shelburne
mesh_terms: D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D000071677:Histidine Kinase; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010766:Phosphorylation; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D065288:Serogroup; D013297:Streptococcus pyogenes / Q000235:genetics* / Q000378:metabolism; D059467:Transcriptome
chemical_list: D001426:Bacterial Proteins; C432143:CsrR protein, Streptococcus pyogenes; D047908:Intracellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; C534547:CovS protein, Streptococcus pyogenes; D000071677:Histidine Kinase