Epidermal growth factor induces tyrosine phosphorylation of epidermal growth factor receptors not occupied with ligand in intact A431 cells

• Published in: FEBS letters 1990-07, Vol.268 (1), p.121-124
• Main Authors: Sorokin, A.B., Reshetnikova, G.F., Kudryavtseva, N.V., Nikolsky, N.N.
• Format: Article
• Language: English
• Subjects: A431 cell; A431 cells; anti-P-Tyr, antiserum against phosphotyrosine; Antiphosphotyrosine antibody; Autophosphorylation; Biological and medical sciences; Cell receptors; Cell structures and functions; EGF, epidermal growth factor; EGF-R, epidermal growth factor receptors; Epidermal Growth Factor - metabolism; Epidermal Growth Factor - pharmacology; Epidermal growth factor receptor; ErbB Receptors - metabolism; Fundamental and applied biological sciences. Psychology; Hormone receptors. Growth factor receptors. Cytokine receptors. Prostaglandin receptors; Humans; In Vitro Techniques; Ligands; Molecular and cellular biology; PBS, phosphate-buffered saline; Phosphorylation; Phosphotyrosine; Tumor Cells, Cultured; Tyrosine - analogs & derivatives; Tyrosine - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(90)80988-U

The mechanism of epidermal growth factor receptor (EGF-R) autophosphorylation in intact A431 cells was studied. We detected epidermal growth factor (EGF) induced tyrosine phosphorylation of EGF-R not occupied with ligand. Cell monolayers were subjected to irradiation after incubation with photoreactive derivative of EGF and uncoupled EGF was extracted by acidic treatment. Subsequent immunoprecipitation with antiphosphotyrosine antibodies resulted in precipitation of both EGF-R complexes with EGF and EGF-R with unoccupied ligand-binding site. The fact of precipitation of EGF-R with unoccupied ligand-binding site in conjunction with our finding of rapid dephosphorylation of EGF-R after EGF extraction by acidic treatment, strongly supports the interpretation that cross-phosphorylation of EGF-R may take place in intact cells.