Lu/BCAM adhesion glycoprotein is a receptor for Escherichia coli Cytotoxic Necrotizing Factor 1 (CNF1)

PLoS Pathog. 2014 Jan;10(1):e1003884. doi: 10.1371/journal.ppat.1003884. Epub 2014 Jan 16.

Abstract

The Cytotoxic Necrotizing Factor 1 (CNF1) is a protein toxin which is a major virulence factor of pathogenic Escherichia coli strains. Here, we identified the Lutheran (Lu) adhesion glycoprotein/basal cell adhesion molecule (BCAM) as cellular receptor for CNF1 by co-precipitation of cell surface molecules with tagged toxin. The CNF1-Lu/BCAM interaction was verified by direct protein-protein interaction analysis and competition studies. These studies revealed amino acids 720 to 1014 of CNF1 as the binding site for Lu/BCAM. We suggest two cell interaction sites in CNF1: first the N-terminus, which binds to p37LRP as postulated before. Binding of CNF1 to p37LRP seems to be crucial for the toxin's action. However, it is not sufficient for the binding of CNF1 to the cell surface. A region directly adjacent to the catalytic domain is a high affinity interaction site for Lu/BCAM. We found Lu/BCAM to be essential for the binding of CNF1 to cells. Cells deficient in Lu/BCAM but expressing p37LRP could not bind labeled CNF1. Therefore, we conclude that LRP and Lu/BCAM are both required for toxin action but with different functions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Toxins / genetics
  • Bacterial Toxins / metabolism*
  • Cell Adhesion Molecules / immunology
  • Cell Adhesion Molecules / metabolism*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli / pathogenicity*
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / metabolism*
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Lutheran Blood-Group System / immunology
  • Lutheran Blood-Group System / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Virulence Factors / genetics
  • Virulence Factors / metabolism*

Substances

  • BCAM protein, human
  • Bacterial Toxins
  • Cell Adhesion Molecules
  • Escherichia coli Proteins
  • Lutheran Blood-Group System
  • Virulence Factors
  • cytotoxic necrotizing factor type 1

Grants and funding

This work was supported by the Deutsche Forschungsgemeinschaft (DFG, Schm 1385/4-2 and SFB850, C2). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.