title: BfpI, BfpJ, and BfpK Minor Pilins Are Important for the Function and Biogenesis of Bundle-Forming Pili Expressed by Enteropathogenic Escherichia coli.
abstract: Enteropathogenic Escherichia coli (EPEC) remains a significant cause of infant diarrheal illness and associated morbidity and mortality in developing countries. EPEC strains are characterized by their ability to colonize the small intestines of their hosts by a multistep program involving initial loose attachment to intestinal epithelial cells followed by an intimate adhesion phase. The initial loose interaction of typical EPEC with host intestinal cells is mediated by bundle-forming pili (BFP). BFP are type 4b pili (T4bP) based on structural and functional properties shared with T4bP expressed by other bacteria. The major structural subunit of BFP is called bundlin, a T4b pilin expressed from the bfpA gene in the BFP operon, which contains three additional genes that encode the pilin-like proteins BfpI, BfpJ, and BfpK. In this study, we show that, in the absence of the BFP retraction ATPase (BfpF), BfpI, BfpJ, and BfpK are dispensable for BFP biogenesis. We also demonstrate that these three minor pilins are incorporated along with bundlin into the BFP filament and contribute to its structural integrity and host cell adhesive properties. The results confirm that previous findings in T4aP systems can be extended to a model T4bP such as BFP.
  
  
  OBJECTIVE
  Bundle-forming pili contribute to the host colonization strategy of enteropathogenic Escherichia coli. The studies described here investigate the role for three minor pilin subunits in the structure and function of BFP in EPEC. The studies also suggest that these subunits could be antigens for vaccine development.
authors.affiliation: Department of Microbiology, Immunology and Infectious Disease, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Claudia F
authors.initials: CF
authors.lastname: Martinez de la Peña
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of Maryland, School of Medicine, Baltimore, Maryland, USA.
authors.forename: Leon
authors.initials: L
authors.lastname: De Masi
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of Maryland, School of Medicine, Baltimore, Maryland, USA.
authors.forename: Shahista
authors.initials: S
authors.lastname: Nisa
authors.affiliation: Department of Microbiology, Immunology and Infectious Disease, University of Calgary, Calgary, Alberta, Canada.
authors.forename: George
authors.initials: G
authors.lastname: Mulvey
authors.affiliation: Department of Microbiology, Immunology and Infectious Disease, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Jesse
authors.initials: J
authors.lastname: Tong
authors.affiliation: Division of Infectious Diseases, Department of Medicine, University of Maryland, School of Medicine, Baltimore, Maryland, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Donnenberg
authors.affiliation: Department of Microbiology, Immunology and Infectious Disease, University of Calgary, Calgary, Alberta, Canada glen.armstrong@ucalgary.ca.
authors.forename: Glen D
authors.initials: GD
authors.lastname: Armstrong
mesh_terms: D054308:Enteropathogenic Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism*; D010861:Fimbriae, Bacterial / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D007150:Immunohistochemistry; D009154:Mutation
chemical_list: C000608621:BfpI protein, E coli; C000608622:BfpJ protein, E coli; C000608623:BfpK protein, E coli; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins