J. Biol. Chem., Vol. 261, Issue 18, 8295-8297, 06, 1986
Suppression of protein tyrosine kinase activity of the epidermal growth factor receptor by epidermal growth factor
M Chinkers and DL Garbers
Epidermal growth factor (EGF) receptor protein kinase activity, estimated
by the use of peptide substrates, was reduced by as much as 70% after the
treatment of intact A431 human carcinoma cells with EGF. The apparent
decrease in protein kinase activity was observed after immunoprecipitation
of the receptor or after purification of the receptor by lectin
chromatography. By the use of [35S]methionine, it was determined that the
total amount of receptor obtained was the same whether or not cells were
treated with EGF. EGF stimulated the purified receptor protein kinase
activity in vitro; however, the EGF-stimulated activity of receptor from
EGF-treated cells continued to be reduced by as much at 70% compared to the
EGF-stimulated activity from untreated cells. The reduction in receptor
protein kinase activity induced by EGF may represent a feedback mechanism
by which responsiveness to the growth factor is regulated.