title: Iron-regulated surface determinant B (IsdB) promotes Staphylococcus aureus adherence to and internalization by non-phagocytic human cells.
abstract: Staphylococcus aureus is a human pathogen that causes invasive and recurring infections. The ability to internalize into and persist within host cells is thought to contribute to infection. Here we report a novel role for the well-characterized iron-regulated surface determinant B (IsdB) protein which we have shown can promote adhesion of 293T, HeLa cells and platelets to immobilized bacteria independently of its ability to bind haemoglobin. IsdB bound to the active form of the platelet integrin αIIb β3 , both on platelets and when the integrin was expressed ectopically in CHO cells. IsdB also promoted bacterial invasion into human cells. This was clearly demonstrated with bacteria lacking fibronectin-binding proteins (FnBPs), which are known to promote invasion in the presence of fibronectin. However, IsdB also contributed significantly to invasion by cells expressing FnBPs in the presence of serum. Thus IsdB appears to be able to interact with the broader family of integrins that bind ligands with the RGD motif and to act as a back up mechanism to promote interactions with mammalian cells.
authors.affiliation: Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Marta
authors.initials: M
authors.lastname: Zapotoczna
authors.forename: Zala
authors.initials: Z
authors.lastname: Jevnikar
authors.forename: Helen
authors.initials: H
authors.lastname: Miajlovic
authors.forename: Janko
authors.initials: J
authors.lastname: Kos
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Foster
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism; D001422:Bacterial Adhesion / Q000502:physiology*; D001792:Blood Platelets / Q000382:microbiology* / Q000473:pathology; D027682:Cation Transport Proteins / Q000502:physiology*; D002478:Cells, Cultured; D005353:Fibronectins / Q000378:metabolism; D057809:HEK293 Cells / Q000382:microbiology* / Q000473:pathology; D006367:HeLa Cells / Q000382:microbiology* / Q000473:pathology; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D013211:Staphylococcus aureus / Q000472:pathogenicity* / Q000502:physiology*
chemical_list: D018829:Adhesins, Bacterial; D027682:Cation Transport Proteins; D005353:Fibronectins; D006454:Hemoglobins; C510010:IsdB protein, Staphylococcus aureus; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; C078635:fibronectin-binding proteins, bacterial