Diphtheria toxin binds to the epidermal growth factor (EGF)-like domain of human heparin-binding EGF-like growth factor/diphtheria toxin receptor and inhibits specifically its mitogenic activity.
The membrane anchored form of human heparin-binding epidermal growth factor-like growth factor (HB-EGF) acts as the diphtheria toxin (DT) receptor. Transfection of human HB-EGF cDNA into mouse LC cells, L cells stably expressing DRAP27, conferred sensitivity to DT, but transfection of mouse HB-EGF cDNA did not. To define the essential regions of HB-EGF that serve as the functional DT receptor, we examined the sensitivity to DT and DT binding of cells expressing several human/mouse HB-EGF chimeras. It was found that DT binds to the EGF-like domain of the human HB-EGF. However, mouse HB-EGF does not serve as a functional DT receptor due to non-conserved amino acid substitutions in this domain. In addition, CRM197, a non-toxic mutant of DT, inhibited strongly the mitogenic activity of the secreted form of human HB-EGF, but not of mouse HB-EGF and other EGF receptor-binding growth factors. These results confirmed further that DT interacts with the EGF-like domain of HB-EGF and that this interaction is specific for human HB-EGF.
Mitamura
T
T
Division of Cell Biology, Kurume University, Fukuoko, Japan.
Higashiyama
S
S
Taniguchi
N
N
Klagsbrun
M
M
Mekada
E
E
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary; D004167:Diphtheria Toxin / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007739:L Cells; D051379:Mice; D008934:Mitogens / Q000037:antagonists & inhibitors*; D008969:Molecular Sequence Data; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*
D018076:DNA, Complementary; D004167:Diphtheria Toxin; C587883:HBEGF protein, human; C587884:Hbegf protein, mouse; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D008934:Mitogens; D011956:Receptors, Cell Surface; D004815:Epidermal Growth Factor; D006493:Heparin