The giant extracellular matrix-binding protein of Staphylococcus epidermidis mediates biofilm accumulation and attachment to fibronectin.
Virulence of nosocomial pathogen Staphylococcus epidermidis is essentially related to formation of adherent biofilms, assembled by bacterial attachment to an artificial surface and subsequent production of a matrix that mediates interbacterial adhesion. Growing evidence supports the idea that proteins are functionally involved in S. epidermidis biofilm accumulation. We found that in S. epidermidis 1585v overexpression of a 460 kDa truncated isoform of the extracellular matrix-binding protein (Embp) is necessary for biofilm formation. Embp is a giant fibronectin-binding protein harbouring 59 Found In Various Architectures (FIVAR) and 38 protein G-related albumin-binding (GA) domains. Studies using defined Embp-positive and -negative S. epidermidis strains proved that Embp is sufficient and necessary for biofilm formation. Further data showed that the FIVAR domains of Embp mediate binding of S. epidermidis to solid-phase attached fibronectin, constituting the first step of biofilm formation on conditioned surfaces. The binding site in fibronectin was assigned to the fibronectin domain type III12. Embp-mediated biofilm formation also protected S. epidermidis from phagocytosis by macrophages. Thus, Embp is a multifunctional cell surface protein that mediates attachment to host extracellular matrix, biofilm accumulation and escape from phagocytosis, and therefore is well suited for promoting implant-associated infections.
Christner
Martin
M
Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
Franke
Gefion C
GC
Schommer
Nina N
NN
Wendt
Ulrike
U
Wegert
Kim
K
Pehle
Philip
P
Kroll
Gesche
G
Schulze
Christian
C
Buck
Friedrich
F
Mack
Dietrich
D
Aepfelbacher
Martin
M
Rohde
Holger
H
D020816:Amino Acid Motifs; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018441:Biofilms / Q000254:growth & development*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D005353:Fibronectins / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D010587:Phagocytosis; D011485:Protein Binding; D025941:Protein Interaction Mapping; D013212:Staphylococcus epidermidis / Q000276:immunology / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology*
D001426:Bacterial Proteins; D002352:Carrier Proteins; C469919:Embp32 protein, Staphylococcus epidermidis; D005353:Fibronectins