title: The hek outer membrane protein of Escherichia coli strain RS218 binds to proteoglycan and utilizes a single extracellular loop for adherence, invasion, and autoaggregation.
abstract: Escherichia coli is the principal gram-negative causative agent of sepsis and meningitis in neonates. The pathogenesis of meningitis due to E. coli K1 involves mucosal colonization, transcytosis of epithelial cells, survival in the bloodstream, and eventually invasion of the meninges. The last two aspects have been well characterized at a molecular level. Less is known about the early stages of pathogenesis, i.e., adhesion to and invasion of epithelial cells. We have previously reported that the Hek protein causes autoaggregation and can mediate adherence to and invasion of epithelial cells. Here, we report that Hek-mediated adherence is dependent on binding to glycosoaminoglycan, in particular, heparin. The ability to hemagglutinate, autoaggregate, adhere, and invade is contingent on a putative 25-amino-acid loop that is exposed to the outside of the bacterial cells.
authors.affiliation: Department of Clinical Microbiology, Trinity College Dublin, St James's Hospital, Dublin 8, Ireland.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Fagan
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Lambert
authors.forename: Stephen G J
authors.initials: SG
authors.lastname: Smith
mesh_terms: D018830:Adhesins, Escherichia coli / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001422:Bacterial Adhesion; D002460:Cell Line; D002809:Chondroitin Sulfates / Q000378:metabolism; D006224:Cricetinae; D016264:Dextran Sulfate / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology*; D004926:Escherichia coli / Q000502:physiology*; D006493:Heparin / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism; D008958:Models, Molecular; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D017384:Sequence Deletion
chemical_list: D018830:Adhesins, Escherichia coli; D002809:Chondroitin Sulfates; D016264:Dextran Sulfate; D006493:Heparin; D006497:Heparan Sulfate; C520238:HEK protein, E coli