title: Demonstration of ligand-dependent signaling by the erbB-3 tyrosine kinase and its constitutive activation in human breast tumor cells.
abstract: The predicted human erbB-3 gene product is closely related to epidermal growth factor receptor (EGFR) and erbB-2, which have been implicated as oncogenes in model systems and human neoplasia. We expressed the erbB-3 coding sequence in NIH 3T3 fibroblasts and identified its product as a 180-kDa glycoprotein, gp180erbB-3. Tunicamycin and pulse-chase experiments revealed that the mature protein was processed by N-linked glycosylation of a 145-kDa erbB-3 core polypeptide. The intrinsic catalytic function of gp180erbB-3 was shown by its ability to autophosphorylate in vitro. Ligand-dependent signaling of its cytoplasmic domain was established employing transfectants that express a chimeric EGFR/erbB-3 protein, gp180EGFR/erbB-3. EGF induced tyrosine phosphorylation of the chimera and promoted soft agar colony formation of such transfectants. These findings combined with the detection of constitutive tyrosine phosphorylation of gp180erbB-3 in 4 of 12 human mammary tumor cell lines implicate the activated erbB-3 product in the pathogenesis of some human malignancies.
authors: Laboratory of Cellular and Molecular Biology, National Cancer Institute, Bethesda, MD 20892.
authors: M H
authors: MH
authors: Kraus
authors: P
authors: P
authors: Fedi
authors: V
authors: V
authors: Starks
authors: R
authors: R
authors: Muraro
authors: S A
authors: SA
authors: Aaronson
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics*; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D005260:Female; D006031:Glycosylation; D006801:Humans; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D009842:Oligopeptides / Q000138:chemical synthesis / Q000276:immunology; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D020893:Receptor, ErbB-3; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D014162:Transfection; D014407:Tumor Cells, Cultured; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D009838:Oligodeoxyribonucleotides; D009842:Oligopeptides; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D014415:Tunicamycin; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D020893:Receptor, ErbB-3