Abstract
To identify proteins that may participate in the activation of the protein kinase Raf, proteins that interact with Raf were selected in a two-hybrid screen. Two members of the 14-3-3 protein family were isolated that interacted with both the amino terminal regulatory regions of Raf and the kinase domain of Raf, but did not compete with the guanine nucleotide-binding protein Ras for binding to Raf. 14-3-3 proteins associated with Raf in mammalian cells and accompanied Raf to the membrane in the presence of activated Ras. In yeast cells expressing Raf and MEK, mammalian 14-3-3 beta or 14-3-3 zeta activated Raf to a similar extent as did expression of Ras. Therefore, 14-3-3 proteins may participate in or be required for the regulation of Raf function. These findings suggest a role for 14-3-3 proteins in Raf-mediated signal transduction.
MeSH terms
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14-3-3 Proteins
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Amino Acid Sequence
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Animals
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Cell Line
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Cell Membrane / enzymology
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Cytosol / enzymology
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Enzyme Activation
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GTP-Binding Proteins / metabolism
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HeLa Cells
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Humans
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MAP Kinase Kinase 1
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Mitogen-Activated Protein Kinase Kinases*
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Molecular Sequence Data
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Nerve Tissue Proteins / metabolism*
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Protein Serine-Threonine Kinases / chemistry
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism*
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Protein-Tyrosine Kinases / genetics
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Protein-Tyrosine Kinases / metabolism
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Proto-Oncogene Proteins / chemistry
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Proto-Oncogene Proteins / metabolism*
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Proto-Oncogene Proteins c-raf
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Recombinant Proteins / metabolism
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / growth & development
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Signal Transduction
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Tyrosine 3-Monooxygenase*
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Zinc Fingers
Substances
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14-3-3 Proteins
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Nerve Tissue Proteins
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Proto-Oncogene Proteins
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Recombinant Proteins
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Tyrosine 3-Monooxygenase
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Protein-Tyrosine Kinases
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Protein Serine-Threonine Kinases
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Proto-Oncogene Proteins c-raf
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MAP Kinase Kinase 1
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MAP2K1 protein, human
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Mitogen-Activated Protein Kinase Kinases
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GTP-Binding Proteins