title: Alpha C protein of group B Streptococcus binds host cell surface glycosaminoglycan and enters cells by an actin-dependent mechanism.
abstract: Group B Streptococcus (GBS) colonizes mucosal surfaces of the human gastrointestinal and gynecological tracts and causes disease in a wide range of patients. Invasive illness occurs after organisms traverse an epithelial boundary and enter deeper tissues. Previously we have reported that the alpha C protein (ACP) on the surface of GBS mediates GBS entry into ME180 cervical epithelial cells and GBS translocation across layers of these cells. We now demonstrate that ACP interacts with host cell glycosaminoglycan (GAG); the interaction of ACP with ME180 cells is inhibited if cells are pretreated with sodium chlorate, an inhibitor of sulfate incorporation, or with heparitinases. The interaction is also inhibited in the presence of soluble heparin or heparan sulfate or host cell-derived GAG. In addition, ACP binds soluble heparin specifically in inhibition and dot blot assays. After interaction with host GAG, soluble ACP enters ME180 cells and fractionates to the eukaryotic cell cytosol. These events are inhibited in cells pretreated with cytochalasin D or with Clostridium difficile toxin B. These data indicate that full-length ACP interacts with ME180 cell GAG and enters the eukaryotic cell cytosol by a mechanism that involves Rho GTPase-dependent actin rearrangements. We suggest that these molecular interactions drive ACP-mediated translocation of GBS across epithelial barriers, thereby facilitating invasive GBS infection.
authors.affiliation: Channing Laboratory and Division of Infectious Diseases, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. mbaron@partners.org
authors.forename: Miriam J
authors.initials: MJ
authors.lastname: Baron
authors.forename: Gilles R
authors.initials: GR
authors.lastname: Bolduc
authors.forename: Marcia B
authors.initials: MB
authors.lastname: Goldberg
authors.forename: Thierry C
authors.initials: TC
authors.lastname: Aupérin
authors.forename: Lawrence C
authors.initials: LC
authors.lastname: Madoff
mesh_terms: D000199:Actins / Q000378:metabolism*; D000954:Antigens, Surface / Q000737:chemistry* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001427:Bacterial Toxins / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002584:Cervix Uteri / Q000166:cytology / Q000382:microbiology; D002704:Chlorates / Q000494:pharmacology; D015638:Cytochalasin D / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D003603:Cytotoxins / Q000378:metabolism; D004072:Digitonin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000382:microbiology; D005260:Female; D005434:Flow Cytometry; D006025:Glycosaminoglycans / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism; D006801:Humans; D007118:Immunoassay; D007700:Kinetics; D018613:Microscopy, Confocal; D011133:Polysaccharide-Lyases / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D013292:Streptococcus agalactiae / Q000378:metabolism*; D013347:Subcellular Fractions; D013997:Time Factors
chemical_list: D000199:Actins; D000954:Antigens, Surface; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D002704:Chlorates; D003603:Cytotoxins; D006025:Glycosaminoglycans; C031815:toxB protein, Clostridium difficile; C077961:alpha C protein, group B streptococci; D015638:Cytochalasin D; D006493:Heparin; D011133:Polysaccharide-Lyases; C021349:heparitinsulfate lyase; D004072:Digitonin; C032706:sodium chlorate