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Fibroblast Growth Factors Stimulate Protein Tyrosine Phosphorylation and Mitogen‐Activated Protein Kinase Activity in Primary Cultures of Hippocampal Neurons
Author(s) -
Creuzet C.,
Loeb J.,
Barbin G.
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.64041541.x
Subject(s) - tyrosine phosphorylation , fibroblast growth factor , basic fibroblast growth factor , mitogen activated protein kinase , biology , microbiology and biotechnology , tyrosine kinase , receptor tyrosine kinase , protein tyrosine phosphatase , phosphorylation , platelet derived growth factor receptor , tyrosine , signal transduction , endocrinology , biochemistry , growth factor , receptor
Fibroblast growth factors (FGFs) are not only mitogens, but they also promote the differentiation of various cell types. For instance, basic FGF (bFGF) provides a critical trophic support for hippocampal neurons in culture. To elicit their biological effects, FGFs interact with high‐affinity receptors that are transmembrane proteins with a cytoplasmic portion containing a tyrosine kinase activity. The tyrosine phosphorylation pattern was examined in primary cultures of hippocampal neurons derived from rat embryos. In these cultures grown for 3 days in the absence of serum, the addition of bFGF causes a rapid increase of tyrosine phosphorylation for various proteins with an optimal level after 5 min of bFGF exposure. Concomitantly, bFGF activates mitogen‐activated protein kinase (MAP kinase) activity measured with a selective MAP kinase peptide. The activity increased rapidly after the addition of bFGF and remained elevated even when cultures were treated for 1 h with bFGF. Both acidic and basic FGF were able to enhance protein tyrosine phosphorylation and MAP kinase activity, whereas nerve growth factor and epidermal growth factor did not elicit any of these responses. These data indicate that some of the transduction signals (i.e., tyrosine phosphorylation and activation of MAP kinase) that have been described for the proliferative effect of FGFs are also involved when FGFs act as trophic factors for postmitotic neurons in culture.