title: Streptococcus pyogenes Escapes Killing from Extracellular Histones through Plasminogen Binding and Activation by Streptokinase.
abstract: Histones are small basic proteins and highly conserved among eukaryotes. Their main function is binding, packaging and organizing of DNA in the nucleus, but extracellular histones are also potent antimicrobial proteins. Here we found that Streptococcus pyogenes - an important human pathogen - protects itself from histone-killing by the acquisition of plasminogen. Plasminogen, bound to the streptococcal surface, efficiently prevents histone-mediated killing. Moreover, the streptokinase/plasminogen complex degrades all classes of histones and abrogates their antibacterial and hemolytic effects. This novel streptokinase-mediated virulence mechanism may contribute to the escape of S. pyogenes from the human innate immune system.
authors.affiliation: University Medicine, Institute of Medical Microbiology, Virology and Hygiene, Rostock University, Rostock, Germany.
authors.forename: Ramona
authors.initials: R
authors.lastname: Nitzsche
authors.forename: Juliane
authors.initials: J
authors.lastname: Köhler
authors.forename: Bernd
authors.initials: B
authors.lastname: Kreikemeyer
authors.forename: Sonja
authors.initials: S
authors.lastname: Oehmcke-Hecht
mesh_terms: D001433:Bacteriolysis; D004789:Enzyme Activation; D005110:Extracellular Space; D055785:Gene Knockdown Techniques; D006461:Hemolysis; D006657:Histones / Q000378:metabolism*; D006801:Humans; D057131:Immune Evasion; D007113:Immunity, Innate; D010958:Plasminogen / Q000378:metabolism*; D011485:Protein Binding; D013290:Streptococcal Infections / Q000276:immunology*; D013297:Streptococcus pyogenes / Q000472:pathogenicity / Q000502:physiology*; D013300:Streptokinase / Q000235:genetics / Q000378:metabolism*; D014774:Virulence
chemical_list: D006657:Histones; D010958:Plasminogen; D013300:Streptokinase