Abstract
The product of the trk proto-oncogene encodes a receptor for nerve growth factor (NGF). Here we show that NGF is a powerful mitogen that can induce resting NIH 3T3 cells to enter S phase, grow in semisolid medium, and become morphologically transformed. These mitogenic effects are absolutely dependent on expression of gp140trk receptors, but do not require the presence of the previously described low affinity NGF receptor. gp140trk also serves as a receptor for the related factor neurotrophin-3 (NT-3), but not for brain-derived neurotrophic factor. Both NGF and NT-3 induce the rapid phosphorylation of gp140trk receptors and the transient expression of c-Fos proteins. However, NT-3 appears to elicit more limited mitogenic responses than NGF. These results indicate that the product of the trk proto-oncogene is sufficient to mediate signal transduction processes induced by NGF and NT-3, at least in proliferating cells.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Brain-Derived Neurotrophic Factor
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Cell Cycle / drug effects*
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Cell Division / drug effects
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Cell Line
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DNA Replication / drug effects
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Mice
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Nerve Growth Factors / genetics
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Nerve Growth Factors / metabolism
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Nerve Growth Factors / pharmacology*
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism
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Nerve Tissue Proteins / pharmacology*
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Phosphorylation
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Plasmids
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / metabolism*
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / metabolism*
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Proto-Oncogene Proteins c-fos
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Proto-Oncogenes*
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Receptor, trkA
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Receptors, Cell Surface / metabolism*
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Receptors, Nerve Growth Factor
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Transfection
Substances
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Brain-Derived Neurotrophic Factor
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Nerve Growth Factors
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Nerve Tissue Proteins
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-fos
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Receptors, Cell Surface
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Receptors, Nerve Growth Factor
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Protein-Tyrosine Kinases
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Receptor, trkA