title: Down-modulation of EGF receptors in cells transformed by the src oncogene.
abstract: The effects of src oncogene expression on epidermal growth factor (EGF) receptors have been investigated in mouse 3T3 and rat-1 fibroblasts. Transformation of both cell types with src resulted in marked reductions in cellular EGF receptor levels, as assayed by either 125I-EGF binding or immunoprecipitation of receptor protein from radiolabeled cell lysates. In contrast to cells transformed by other types of retroviral oncogenes, the loss of EGF receptors in the src-transformed cells did not appear to be due to secreted transforming growth factor-alpha (TGF-alpha), since such factors were undetectable in culture fluids from the src-transformed cells. By several criteria of transformation, an EGF-receptorless cell line infected with src was shown to be transformed, suggesting that EGF receptors themselves are not obligatory to the src transformation process. We suggest that pp60src down-modulates EGF receptors by an intracellular mechanism and that the loss of the receptors is symptomatic of more general effects of pp60src on the machinery of growth regulation.
mesh_terms: D000818:Animals; D001358:Avian Sarcoma Viruses / Q000502:physiology; D002460:Cell Line; D002472:Cell Transformation, Viral; D003470:Culture Media / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000172:deficiency / Q000378:metabolism*; D005347:Fibroblasts / Q000378:metabolism*; D051379:Mice; D015688:Oncogene Protein pp60(v-src); D010455:Peptides / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D051381:Rats; D012191:Retroviridae Proteins / Q000502:physiology*; D015291:Transforming Growth Factors
chemical_list: D003470:Culture Media; D010455:Peptides; D012191:Retroviridae Proteins; D004815:Epidermal Growth Factor; D015291:Transforming Growth Factors; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D015688:Oncogene Protein pp60(v-src)