Regulation of kinase activity of 3-phosphoinositide-dependent protein kinase-1 by binding to 14-3-3.
3-Phosphoinositide-dependent protein kinase-1 (PDK1) plays a central role in activating the protein kinase A, G, and C subfamily. In particular, PDK1 plays an important role in regulating the Akt survival pathway by phosphorylating Akt on Thr-308. PDK1 kinase activity was thought to be constitutively active; however, recent reports suggested that ... its activity is regulated by binding to other proteins, such as protein kinase C-related kinase-2 (PRK2), p90 ribosomal protein S6 kinase-2 (RSK2), and heat-shock protein 90 (Hsp90). Here we report that PDK1 binds to 14-3-3 proteins in vivo and in vitro through the sequence surrounding Ser-241, a residue that is phosphorylated by itself and is critical for its kinase activity. Mutation of PDK1 to increase its binding to 14-3-3 decreased its kinase activity in vivo. By contrast, mutation of PDK1 to decrease its interaction with 14-3-3 resulted in increased PDK1 kinase activity. Moreover, incubation of wild-type PDK1 with recombinant 14-3-3 in vitro decreased its kinase activity. These data indicate that PDK1 kinase activity is negatively regulated by binding to 14-3-3 through the PDK1 autophosphorylation site Ser-241.
Mesh Terms:
14-3-3 Proteins, 3T3 Cells, Animals, Binding Sites, Blotting, Western, COS Cells, Catalysis, Cell Line, DNA, Complementary, Down-Regulation, Gene Expression Regulation, Enzymologic, Genetic Vectors, Glutathione Transferase, HSP90 Heat-Shock Proteins, Humans, Mice, Mutagenesis, Site-Directed, Mutation, Peptides, Plasmids, Precipitin Tests, Protein Binding, Protein Isoforms, Protein Kinase C, Protein-Serine-Threonine Kinases, Recombinant Fusion Proteins, Recombinant Proteins, Ribosomal Protein S6 Kinases, 90-kDa, Serine, Signal Transduction, Transfection, Tumor Cells, Cultured, Tyrosine 3-Monooxygenase
14-3-3 Proteins, 3T3 Cells, Animals, Binding Sites, Blotting, Western, COS Cells, Catalysis, Cell Line, DNA, Complementary, Down-Regulation, Gene Expression Regulation, Enzymologic, Genetic Vectors, Glutathione Transferase, HSP90 Heat-Shock Proteins, Humans, Mice, Mutagenesis, Site-Directed, Mutation, Peptides, Plasmids, Precipitin Tests, Protein Binding, Protein Isoforms, Protein Kinase C, Protein-Serine-Threonine Kinases, Recombinant Fusion Proteins, Recombinant Proteins, Ribosomal Protein S6 Kinases, 90-kDa, Serine, Signal Transduction, Transfection, Tumor Cells, Cultured, Tyrosine 3-Monooxygenase
J. Biol. Chem.
Date: Oct. 18, 2002
PubMed ID: 12177059
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