UpaG, a new member of the trimeric autotransporter family of adhesins in uropathogenic Escherichia coli

J Bacteriol. 2008 Jun;190(12):4147-61. doi: 10.1128/JB.00122-08. Epub 2008 Apr 18.


The ability of Escherichia coli to colonize both intestinal and extraintestinal sites is driven by the presence of specific virulence factors, among which are the autotransporter (AT) proteins. Members of the trimeric AT adhesin family are important virulence factors for several gram-negative pathogens and mediate adherence to eukaryotic cells and extracellular matrix (ECM) proteins. In this study, we characterized a new trimeric AT adhesin (UpaG) from uropathogenic E. coli (UPEC). Molecular analysis of UpaG revealed that it is translocated to the cell surface and adopts a multimeric conformation. We demonstrated that UpaG is able to promote cell aggregation and biofilm formation on abiotic surfaces in CFT073 and various UPEC strains. In addition, UpaG expression resulted in the adhesion of CFT073 to human bladder epithelial cells, with specific affinity to fibronectin and laminin. Prevalence analysis revealed that upaG is strongly associated with E. coli strains from the B2 and D phylogenetic groups, while deletion of upaG had no significant effect on the ability of CFT073 to colonize the mouse urinary tract. Thus, UpaG is a novel trimeric AT adhesin from E. coli that mediates aggregation, biofilm formation, and adhesion to various ECM proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Escherichia coli / chemistry
  • Adhesins, Escherichia coli / genetics
  • Adhesins, Escherichia coli / metabolism*
  • Amino Acid Sequence
  • Animals
  • Bacterial Adhesion / genetics
  • Bacterial Adhesion / physiology
  • Biofilms / growth & development
  • Blotting, Western
  • Cell Line
  • Dimerization
  • Epithelial Cells / metabolism
  • Epithelial Cells / microbiology
  • Escherichia coli / genetics
  • Escherichia coli / growth & development
  • Escherichia coli / metabolism
  • Escherichia coli Infections / metabolism
  • Escherichia coli Infections / microbiology
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • Female
  • Fibronectins / metabolism
  • HeLa Cells
  • Humans
  • Laminin / metabolism
  • Mice
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Urinary Tract / microbiology


  • Adhesins, Escherichia coli
  • Escherichia coli Proteins
  • Fibronectins
  • Laminin