Transforming growth factor-alpha binds to the epidermal growth factor receptor in gastric mucosa.
The ability of transforming growth factor-alpha (TGF-alpha) to interact with the gastric mucosal epidermal growth factor (EGF) receptor was investigated using a mucosal membrane preparation. TGF-alpha inhibited specific binding of [125I]EGF to its receptor, but the IC50 for TGF-alpha was at least 100 fold greater than that observed for unlabeled EGF. Cross-linking studies revealed no attachment of [125I]TGF-alpha to EGF-receptor size components, and the unlabeled TGF-alpha was only weakly effective in inhibiting cross-linking of [125I]EGF to the 170 kDa receptor. However, when the cytosolic fraction was reconstituted with the membrane preparation, an enhancement in binding of [125I]TGF-alpha to the EGF receptor occurred in a manner dependent on the concentration of cytosolic protein. Hence the binding characteristics of TGF-alpha to the EGF receptor in gastric mucosa are different from those for EGF.
Bielanski
W J
WJ
Research Center, New Jersey Dental School, University of Medicine and Dentistry of New Jersey, Newark 07103-2425.
Keogh
J P
JP
Wang
S L
SL
Liu
J
J
Konturek
S J
SJ
Slomiany
A
A
Slomiany
B L
BL
D000818:Animals; D001667:Binding, Competitive / Q000502:physiology; D003432:Cross-Linking Reagents; D003600:Cytosol / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D016211:Transforming Growth Factor alpha / Q000378:metabolism*
D003432:Cross-Linking Reagents; D007457:Iodine Radioisotopes; D016211:Transforming Growth Factor alpha; D066246:ErbB Receptors