Inhibition of epidermal growth factor-dependent protein tyrosine phosphorylation by phorbol myristate acetate is mediated by protein tyrosine phosphatase activity.
Incubation of HER14 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 cell are pre-incubated with a combination of Na3VO4 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.
Errasfa
M
M
Department of Pharmacology, New York University Medical Center, NY 10016.
Stern
A
A
D016475:3T3 Cells; D000818:Animals; D002460:Cell Line; D004533:Egtazic Acid / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D051379:Mice; D010766:Phosphorylation; D019000:Phosphotyrosine; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D012969:Sodium Fluoride / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism; D014638:Vanadates / Q000494:pharmacology
D019000:Phosphotyrosine; D014638:Vanadates; D014443:Tyrosine; D004533:Egtazic Acid; D004815:Epidermal Growth Factor; D012969:Sodium Fluoride; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D017027:Protein Tyrosine Phosphatases; D013755:Tetradecanoylphorbol Acetate