Lu/BCAM adhesion glycoprotein is a receptor for Escherichia coli Cytotoxic Necrotizing Factor 1 (CNF1).
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.
Institute for Experimental and Clinical Pharmacology and Toxicology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany ; Biological Faculty, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.
Marianne
M
Piteau
Institute for Experimental and Clinical Pharmacology and Toxicology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.
Panagiotis
P
Papatheodorou
Institute for Experimental and Clinical Pharmacology and Toxicology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.
Carsten
C
Schwan
Rudolf-Virchow-Zentrum für Experimentelle Biomedizin, Universität Würzburg, Würzburg, Germany.
Andreas
A
Schlosser
Institute for Experimental and Clinical Pharmacology and Toxicology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany ; BIOSS (Centre for Biological Signalling Studies), Freiburg, Germany.
Klaus
K
Aktories
Institute for Experimental and Clinical Pharmacology and Toxicology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.
Gudula
G
Schmidt
D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000276:immunology / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008188:Lutheran Blood-Group System / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
C090228:BCAM protein, human; D001427:Bacterial Toxins; D015815:Cell Adhesion Molecules; D029968:Escherichia coli Proteins; D008188:Lutheran Blood-Group System; D037521:Virulence Factors; C060296:cytotoxic necrotizing factor type 1