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Epidermal growth factor induces tyrosine phosphorylation of epidermal growth factor receptors not occupied with ligand in intact A431 cells
Author(s) -
Sorokin A.B.,
Reshetnikova G.F.,
Kudryavtseva N.V.,
Nikolsky N.N.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80988-u
Subject(s) - epidermal growth factor , autophosphorylation , a431 cells , phosphorylation , tyrosine phosphorylation , dephosphorylation , ligand (biochemistry) , immunoprecipitation , epidermal growth factor receptor , receptor , chemistry , tyrosine , biology , microbiology and biotechnology , biochemistry , cell , cell cycle , protein kinase a , oncogene , gene , phosphatase
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.