Characterization of a breast cancer cell differentiation factor that specifically activates the HER4/p180erbB4 receptor.
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Culouscou JM, Plowman GD, Carlton GW, Green JM, Shoyab M
Characterization of a breast cancer cell differentiation factor that specifically activates the HER4/p180erbB4 receptor.
J Biol Chem. 1993 Sep 5;268(25):18407-10.
- PubMed ID
- 7689552 [ View in PubMed]
- Abstract
We recently reported the molecular cloning of HER4/p180erbB4, a new member of the epidermal growth factor receptor family, as well as its activation by a partially purified ligand (Plowman, G. D., Culouscou, J.-M., Whitney, G. S., Green, J. M., Carlton, G. W., Foy, L., Neubauer, M. G., and Shoyab, M. (1993) Proc. Natl. Acad. Sci. U. S. A. 90, 1746-1750). In this report we describe the purification to homogeneity of a 45-kDa protein (p45) that induces the differentiation of MDA-MB-453 human breast cancer cells and stimulates the tyrosine phosphorylation of p180erbB4, the HER4-encoded protein. Hydrophobic interaction, ion-exchange, heparin, and size exclusion chromatographies were used to purify this p180erbB4 activator to homogeneity. N-terminal amino acid sequencing suggests that p45 is related to heregulin, a recently reported ligand for p185erbB2. Binding and cross-linking experiments demonstrated that p45 specifically binds to cells expressing recombinant p180erbB4 and not cells expressing recombinant p185erbB2.