Calcium in the action of growth factors.
The proliferation of cells in vivo and in culture is regulated by polypeptide growth factors, such as epidermal growth factor (EGF) and platelet-derived growth factor (PDGF). Binding of growth factors to their specific cell-surface receptors initiates a cascade of biochemical events in the cell which ultimately leads to DNA synthesis and cell division. Immediate consequences of receptor activation include tyrosine-specific protein phosphorylations, a sustained increase in cytoplasmic pH and a transient rise in cytoplasmic free Ca2+. The PDGF-induced Ca2+ signal is due to Ca2+ release from intracellular stores, whereas EGF seems to activate a voltage-independent Ca2+ channel in the plasma membrane. Monoclonal antibodies to the EGF receptor that stimulate the tyrosine-specific protein kinase fail to raise [Ca2+]i and are not mitogenic for quiescent cells. These results suggest that activation of the EGF receptor tyrosine kinase is not sufficient for the induction of a Ca2+ signal, and that the rise in [Ca2+]i is indispensable for cell proliferation.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects*; D002478:Cells, Cultured; D006133:Growth Substances / Q000494:pharmacology*; D007700:Kinetics; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D006133:Growth Substances; D011505:Protein-Tyrosine Kinases; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium