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EGF and insulin action in fibroblasts
Author(s) -
L'Allemain Gilles,
Pouysségur Jacques
Publication year - 1986
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(86)80354-4
Subject(s) - inositol , epidermal growth factor , stimulation , thrombin , dna synthesis , inositol phosphate , phospholipase c , endocrinology , medicine , insulin , phosphatidylinositol , biology , hamster , chemistry , biochemistry , dna , signal transduction , receptor , platelet
Chinese hamster lung fibroblasts (CHL) arrested in G 0 by serum starvation reinitiate DNA synthesis in response to either EGF, thrombin or serum. Arrested cells, prelabelled to equilibrium with [ 3 H]inositol and receiving 20 mM LiCl prior stimulation, released rapidly large amounts of inositol phosphates when stimulated with thrombin or serum. In sharp contrast, EGF alone, or in association with insulin, failed to induce phosphoinositide breakdown at either early or late stages of EGF stimulation or in growing cells in EGF‐supplemented serum‐free medium. Phospholipase C remained, however, highly activatable by thrombin at all stages of EGF stimulation. Since EGF and thrombin are equally potent mitogens for CHL, we conclude that hydrolysis of polyphosphoinositides is not an exclusive signalling pathway for commitment to DNA replication and cell division.