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Inhibition of epidermal growth factor‐dependent protein tyrosine phosphorylation by phorbol myristate acetate is mediated by protein tyrosine phosphatase activity
Author(s) -
Errasfa Mourad,
Stern Arnold
Publication year - 1994
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(94)80374-9
Subject(s) - protein tyrosine phosphatase , epidermal growth factor , phosphorylation , tyrosine , chemistry , tyrosine phosphorylation , phosphatase , protein phosphorylation , biochemistry , protein kinase a , receptor
Incubation of HER 14 cells with phorbol myristate acetate (PMA) decreases epidermal growth factor (EGF)‐dependent protein tyrosine phosphorylation, except for a 40‐kDa MAP kinase II‐like protein, whose tyrosine phosphorylation is further enhanced. The inhibitory effect of PMA on EGF‐dependent protein tyrosine phosphorylation is reversed if cells are pre‐incubated with a combination of Na 3 VO 4 and NaF, two known inhibitors of protein tyrosine phosphatase activity. Protein tyrosine phosphatase activity of cell homogenate was measured on immunopurified EGF receptor, and was found to be enhanced in PMA‐treated cells. These data suggest that the inhibitory effect of PMA on EGF‐dependent protein tyrosine phosphorylation in HER14 cells may be mediated by protein tyrosine phosphatase activity.