title: Subcellular localization of the Staphylococcus aureus heme iron transport components IsdA and IsdB.
abstract: Staphylococcus aureus is a human pathogen that represents a tremendous threat to global public health. An important aspect of S. aureus pathogenicity is the ability to acquire iron from its host during infection. In vertebrates, iron is sequestered predominantly within heme, the majority of which is bound by hemoglobin. To acquire iron, S. aureus binds hemoglobin, removes heme, and transports it into the cytoplasm, where heme is degraded. This process is carried out by the iron-regulated surface determinant system (Isd); however, the mechanism by which hemoglobin recognition occurs is not completely understood. Here we report that the surface receptor components of the Isd system, IsdA and IsdB, physically interact with each other and are anchored to a discrete location within the cell wall. This organized localization pattern is dependent upon the iron status of the bacterium. Furthermore, we have found that hemoglobin colocalizes with IsdB at discrete sites within the cell wall. Virulence studies revealed that IsdB is required for the efficient colonization of the heart and that IsdB is differentially expressed within infected organs, suggesting that S. aureus experiences various degrees of iron starvation depending on the site of infection. These findings significantly expand our understanding of hemoglobin iron acquisition and demonstrate an orchestrated pattern of regulation and localization for the S. aureus heme iron acquisition system.
authors.affiliation: Department of Microbiology and Immunology, Vanderbilt University Medical School, Medical Center North, Nashville, Tennessee 37232, USA.
authors.forename: Gleb
authors.initials: G
authors.lastname: Pishchany
authors.forename: Susan E
authors.initials: SE
authors.lastname: Dickey
authors.forename: Eric P
authors.initials: EP
authors.lastname: Skaar
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis*; D027682:Cation Transport Proteins / Q000032:analysis*; D002473:Cell Wall / Q000737:chemistry; D006418:Heme / Q000378:metabolism; D006454:Hemoglobins / Q000032:analysis; D007501:Iron / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D011485:Protein Binding; D025941:Protein Interaction Mapping; D013203:Staphylococcal Infections / Q000382:microbiology; D013211:Staphylococcus aureus / Q000737:chemistry* / Q000378:metabolism; D014774:Virulence
chemical_list: D000942:Antigens, Bacterial; D027682:Cation Transport Proteins; D006454:Hemoglobins; C512791:IsdA protein, Staphylococcus aureus; C510010:IsdB protein, Staphylococcus aureus; D006418:Heme; D007501:Iron