title: The metalloprotease SepA governs processing of accumulation-associated protein and shapes intercellular adhesive surface properties in Staphylococcus epidermidis.
abstract: The otherwise harmless skin inhabitant Staphylococcus epidermidis is a major cause of healthcare-associated medical device infections. The species' selective pathogenic potential depends on its production of surface adherent biofilms. The Cell wall-anchored protein Aap promotes biofilm formation in S. epidermidis, independently from the polysaccharide intercellular adhesin PIA. Aap requires proteolytic cleavage to act as an intercellular adhesin. Whether and which staphylococcal proteases account for Aap processing is yet unknown. Here, evidence is provided that in PIA-negative S. epidermidis 1457Δica, the metalloprotease SepA is required for Aap-dependent S. epidermidis biofilm formation in static and dynamic biofilm models. qRT-PCR and protease activity assays demonstrated that under standard growth conditions, sepA is repressed by the global regulator SarA. Inactivation of sarA increased SepA production, and in turn augmented biofilm formation. Genetic and biochemical analyses demonstrated that SepA-related induction of biofilm accumulation resulted from enhanced Aap processing. Studies using recombinant proteins demonstrated that SepA is able to cleave the A domain of Aap at residue 335 and between the A and B domains at residue 601. This study identifies the mechanism behind Aap-mediated biofilm maturation, and also demonstrates a novel role for a secreted staphylococcal protease as a requirement for the development of a biofilm.
authors.affiliation: Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Paharik
authors.affiliation: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Marta
authors.initials: M
authors.lastname: Kotasinska
authors.affiliation: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Both
authors.affiliation: Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Tra-My N
authors.initials: TN
authors.lastname: Hoang
authors.affiliation: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Henning
authors.initials: H
authors.lastname: Büttner
authors.affiliation: Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Paroma
authors.initials: P
authors.lastname: Roy
authors.affiliation: Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Fey
authors.affiliation: Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Horswill
authors.affiliation: Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Rohde
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D008666:Metalloendopeptidases / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D013212:Staphylococcus epidermidis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial; C113579:polysaccharide intercellular adhesin; D008666:Metalloendopeptidases; C081903:SepA protein, Staphylococcus epidermidis