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Phosphorylation of elF‐4E and initiation of protein synthesis in P19 embryonal carcinoma cells
Author(s) -
Kleijn Miranda,
Voorma Harry O.,
Thomas Adri A. M.
Publication year - 1995
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240590405
Subject(s) - phosphorylation , retinoic acid , signal transduction , protein phosphorylation , p19 cell , microbiology and biotechnology , protein biosynthesis , biology , chemistry , cellular differentiation , phosphorylation cascade , biochemistry , protein kinase a , adult stem cell , gene
Mitogenic stimulation of protein synthesis is accompanied by an increase in elF‐4E phosphorylation. The effect on protein synthesis by induction of differentiation is less well known. We treated P19 embryonal carcinoma cells with the differentiating agent retinoic acid and found that protein synthesis increased during the first hour of addition. However, the phosphorylation state, as well as the turnover of phosphate on elF‐4E, remained unchanged. Apparently, the change in protein synthesis after RA addition is regulated by another mechanism than elF‐4E phosphorylation. By using P19 cells overexpressing the EGF receptor, we show that the signal transduction pathway that leads to phosphorylation of elF‐4E is present in P19 cells; the EGF‐induced change in phosphorylation of elF‐4E in these cells is likely to be regulated by a change in elF‐4E phosphatase activity. These results suggest that the onset of retinoic acid‐induced differentiation is triggered by a signal transduction pathway which involves changes in protein synthesis, but not elF‐4E phosphorylation. © 1995 Wiley‐Liss, Inc.