title: Differential protein phosphorylation in induction of thyroid cell proliferation by thyrotropin, epidermal growth factor, or phorbol ester.
abstract: Protein phosphorylation was studied in primary cultures of thyroid epithelial cells after the addition of different mitogens: thyrotropin (TSH) acting through cyclic AMP, epidermal growth factor (EGF), or 12-O-tetradecanoylphorbol-13-acetate (TPA). EGF or TPA increased the phosphorylation of five common polypeptides. Among these, two 42-kilodalton proteins contained phosphotyrosine and phosphoserine with or without phosphothreonine. Their characteristics suggested that they are similar to the two 42-kilodalton target proteins for tyrosine protein phosphorylation demonstrated in fibroblasts in response to mitogens. No common phosphorylated proteins were detected in TSH-treated cells and in EGF- or TPA-treated cells. The differences in the protein phosphorylation patterns in response to TSH, EGF, and TPA suggested that the newly emerging cyclic AMP-mediated mitogenic pathway is distinct from the better known growth factor- and tumor promoter-induced pathways.
authors.affiliation: Institute of Interdisciplinary Research, School of Medicine, Free University of Brussels, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Contor
authors.forename: F
authors.initials: F
authors.lastname: Lamy
authors.forename: R
authors.initials: R
authors.lastname: Lecocq
authors.forename: P P
authors.initials: PP
authors.lastname: Roger
authors.forename: J E
authors.initials: JE
authors.lastname: Dumont
mesh_terms: D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D008970:Molecular Weight; D010750:Phosphoproteins / Q000032:analysis / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D013972:Thyrotropin / Q000494:pharmacology*
chemical_list: D010750:Phosphoproteins; D004815:Epidermal Growth Factor; D013972:Thyrotropin; D011494:Protein Kinases; D013755:Tetradecanoylphorbol Acetate