title: Regulation of hemolysin expression and virulence of Staphylococcus aureus by a serine/threonine kinase and phosphatase.
abstract: Exotoxins, including the hemolysins known as the alpha (alpha) and beta (beta) toxins, play an important role in the pathogenesis of Staphylococcus aureus infections. A random transposon library was screened for S. aureus mutants exhibiting altered hemolysin expression compared to wild type. Transposon insertions in 72 genes resulting in increased or decreased hemolysin expression were identified. Mutations inactivating a putative cyclic di-GMP synthetase and a serine/threonine phosphatase (Stp1) were found to reduce hemolysin expression, and mutations in genes encoding a two component regulator PhoR, LysR family transcriptional regulator, purine biosynthetic enzymes and a serine/threonine kinase (Stk1) increased expression. Transcription of the hla gene encoding alpha toxin was decreased in a Deltastp1 mutant strain and increased in a Deltastk1 strain. Microarray analysis of a Deltastk1 mutant revealed increased transcription of additional exotoxins. A Deltastp1 strain is severely attenuated for virulence in mice and elicits less inflammation and IL-6 production than the Deltastk1 strain. In vivo phosphopeptide enrichment and mass spectrometric analysis revealed that threonine phosphorylated peptides corresponding to Stk1, DNA binding histone like protein (HU), serine-aspartate rich fibrinogen/bone sialoprotein binding protein (SdrE) and a hypothetical protein (NWMN_1123) were present in the wild type and not in the Deltastk1 mutant. Collectively, these studies suggest that Stk1 mediated phosphorylation of HU, SrdE and NWMN_1123 affects S. aureus gene expression and virulence.
authors.affiliation: Department of Pediatric Infectious Diseases, University of Washington and Seattle Children's Hospital Research Institute, Seattle, Washington, USA.
authors.forename: Kellie
authors.initials: K
authors.lastname: Burnside
authors.forename: Annalisa
authors.initials: A
authors.lastname: Lembo
authors.forename: Melissa
authors.initials: M
authors.lastname: de Los Reyes
authors.forename: Anton
authors.initials: A
authors.lastname: Iliuk
authors.forename: Nguyen-Thao
authors.initials: NT
authors.lastname: Binhtran
authors.forename: James E
authors.initials: JE
authors.lastname: Connelly
authors.forename: Wan-Jung
authors.initials: WJ
authors.lastname: Lin
authors.forename: Byron Z
authors.initials: BZ
authors.lastname: Schmidt
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Richardson
authors.forename: Ferric C
authors.initials: FC
authors.lastname: Fang
authors.forename: Weiguo Andy
authors.initials: WA
authors.lastname: Tao
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Rajagopal
mesh_terms: D020869:Gene Expression Profiling; D006460:Hemolysin Proteins / Q000235:genetics / Q000378:metabolism*; D006461:Hemolysis; D013058:Mass Spectrometry; D009154:Mutation; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000201:enzymology / Q000378:metabolism / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D006460:Hemolysin Proteins; D017346:Protein Serine-Threonine Kinases; D010749:Phosphoprotein Phosphatases