title: The surface protease PgtE of Salmonella enterica affects complement activity by proteolytically cleaving C3b, C4b and C5.
abstract: Complement activity in mammalian serum is fundamentally based on three homologous components C3b, C4b and C5. During systemic infection, the gastrointestinal pathogen Salmonella enterica disseminates within host phagocytic cells but also extracellularly. Consequently, systemic Salmonella transiently confronts the complement system. We show here that the surface protease PgtE of S. enterica proteolytically cleaves C3b, C4b and C5 and that the expression of PgtE enhances bacterial resistance to human serum. Degradation of C3b was further enhanced by PgtE-mediated plasminogen activation.
authors.affiliation: Department of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9c, P.O. Box 56 FIN-00014, 00014 Helsinki, Finland. paivi.ramu@helsinki.fi <paivi.ramu@helsinki.fi>
authors.forename: Päivi
authors.initials: P
authors.lastname: Ramu
authors.forename: Rauna
authors.initials: R
authors.lastname: Tanskanen
authors.forename: Mikko
authors.initials: M
authors.lastname: Holmberg
authors.forename: Kaarina
authors.initials: K
authors.lastname: Lähteenmäki
authors.forename: Timo K
authors.initials: TK
authors.lastname: Korhonen
authors.forename: Seppo
authors.initials: S
authors.lastname: Meri
mesh_terms: D000954:Antigens, Surface / Q000502:physiology; D001426:Bacterial Proteins / Q000502:physiology*; D003179:Complement C3b / Q000378:metabolism*; D015935:Complement C4b / Q000378:metabolism*; D003182:Complement C5 / Q000378:metabolism*; D010450:Endopeptidases / Q000502:physiology*; D006801:Humans; D007113:Immunity, Innate; D050296:Microbial Viability; D010958:Plasminogen / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D019779:Salmonella enterica / Q000201:enzymology* / Q000276:immunology / Q000378:metabolism; D044967:Serum / Q000276:immunology
chemical_list: D000954:Antigens, Surface; D001426:Bacterial Proteins; D003182:Complement C5; D003179:Complement C3b; D015935:Complement C4b; D010958:Plasminogen; D010450:Endopeptidases; C411337:PgtE protein, Salmonella enterica