Protein translocation into host epithelial cells by infecting enteropathogenic Escherichia coli

Mol Microbiol. 1998 Apr;28(1):143-55. doi: 10.1046/j.1365-2958.1998.00782.x.


Enteropathogenic Escherichia coli (EPEC) causes diarrhoea in young children. EPEC induces the formation of actin pedestal in infected epithelial cells. A type III protein secretion system and several proteins that are secreted by this system, including EspB, are involved in inducing the formation of the actin pedestals. We have demonstrated that contact of EPEC with HeLa cells is associated with the induction of production and secretion of EspB. Shortly after infection, EPEC initiates translocation of EspB, and EspB fused to the CyaA reporter protein (EspB-CyaA), into the host cell. The translocated EspB was distributed between the membrane and the cytoplasm of the host cell. Translocation was strongly promoted by attachment of EPEC to the host cell, and both attachment factors of EPEC, intimin and the bundle-forming pili, were needed for full translocation efficiency. Translocation and secretion of EspB and EspB-CyaA were abolished in mutants deficient in components of the type III protein secretion system, including sepA and sepB mutants. EspB-CyaA was secreted but not translocated by an espB mutant. These results indicate that EspB is both translocated and required for protein translocation by EPEC.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adenylate Cyclase Toxin
  • Adhesins, Bacterial*
  • Antibodies, Bacterial / immunology
  • Bacterial Adhesion / genetics
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Outer Membrane Proteins / metabolism*
  • Bacterial Proteins / metabolism
  • Carrier Proteins*
  • Cell Fractionation
  • Cell Membrane / metabolism
  • Cyclic AMP / analysis
  • Cyclic AMP / metabolism
  • Cytoplasm / metabolism
  • Epithelial Cells / metabolism
  • Epithelial Cells / microbiology*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Escherichia coli / pathogenicity*
  • Escherichia coli Proteins*
  • Fimbriae, Bacterial / physiology
  • Genes, Bacterial
  • Green Fluorescent Proteins
  • HeLa Cells
  • Humans
  • Immunoblotting
  • Luminescent Proteins
  • Microscopy, Confocal
  • Protein Precursors / metabolism
  • Protein Processing, Post-Translational
  • Recombinant Fusion Proteins / metabolism
  • Recombination, Genetic


  • Adenylate Cyclase Toxin
  • Adhesins, Bacterial
  • Antibodies, Bacterial
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Carrier Proteins
  • EaeB protein, E coli
  • Escherichia coli Proteins
  • Luminescent Proteins
  • Protein Precursors
  • Recombinant Fusion Proteins
  • eaeA protein, E coli
  • Green Fluorescent Proteins
  • Cyclic AMP