Studies of epidermal growth factor (EGF) receptor in plasma membrane from rat liver and hepatoma tissues.
Plasma membrane purified from Buffalo rat liver tissue not only had the ability to bind 125I-EGF (2.77 pg of EGF/mg of membrane protein), but also exhibited both high (Kd = 0.08 nM) and low (Kd = 5.67 nM) affinity receptors. However, the binding of EGF to hepatoma plasma membrane was insignificant. EGF receptor in plasma membrane from normal liver tissue was identified by ECL Western blotting using monoclonal anti-EGF receptor antibody and phosphorylated via the stimulation of EGF. This phosphorylation was inhibited by genistein, a tyrosine kinase inhibitor. However, these effects were not observed in hepatoma cell membrane. These results suggest that plasma membrane purified from normal rat liver tissue has a high level of functional EGF receptor, whereas, hepatoma plasma membrane lacks the receptor.
Department of Biochemistry, National University of Singapore.
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Yang
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Mack
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Cheng
D000818:Animals; D000911:Antibodies, Monoclonal; D001665:Binding Sites; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003720:Densitometry; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D066246:ErbB Receptors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019833:Genistein; D007529:Isoflavones / Q000494:pharmacology; D008099:Liver / Q000378:metabolism* / Q000648:ultrastructure; D008113:Liver Neoplasms / Q000378:metabolism*; D008970:Molecular Weight; D009368:Neoplasm Transplantation; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D051381:Rats; D011915:Rats, Inbred BUF; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D007529:Isoflavones; D019833:Genistein; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases