Binding of 14-3-3beta regulates the kinase activity and subcellular localization of testicular protein kinase 1.
Testicular protein kinase 1 (TESK1) is a serine/threonine kinase that phosphorylates cofilin and induces actin cytoskeletal reorganization. The kinase activity of TESK1 is stimulated by integrin-mediated signaling pathways, but the mechanism of regulation has remained unknown. By using the yeast two-hybrid system, we identified 14-3-3beta to be the binding protein ... of TESK1. Specific interaction between TESK1 and 14-3-3beta became evident in in vitro and in vivo co-precipitation assays. 14-3-3beta interacts with TESK1 through the C-terminal region of TESK1 and in a manner dependent on the phosphorylation of Ser-439 within an RXXSXP motif. Binding of 14-3-3beta inhibited the kinase activity of TESK1. During cell spreading on fibronectin, the TESK1/14-3-3beta interaction significantly decreased, in a time course that inversely correlated with increase in TESK1 kinase activity. Thus, the dissociation of 14-3-3beta from a TESK1/14-3-3beta complex is likely to be involved in the integrin-mediated TESK1 activation. In HeLa cells, TESK1, together with 14-3-3beta, accumulated at the cell periphery when cells were plated on fibronectin, whereas they were diffusely distributed in the cytoplasm in the case of non-stimulated cells. We propose that 14-3-3beta plays important roles in regulating the kinase activity of TESK1 and localizing TESK1 to cell adhesion sites following integrin stimulation.
Mesh Terms:
14-3-3 Proteins, Amino Acid Sequence, Animals, COS Cells, Cell Adhesion, Cell Line, Cytoskeleton, Gene Expression Regulation, Enzymologic, Glutathione Transferase, Hela Cells, Humans, Immunoblotting, Integrins, Microscopy, Fluorescence, Models, Biological, Molecular Sequence Data, Multigene Family, Plasmids, Precipitin Tests, Protein Binding, Protein-Serine-Threonine Kinases, Recombinant Fusion Proteins, Serine, Signal Transduction, Transfection, Two-Hybrid System Techniques, Tyrosine 3-Monooxygenase
14-3-3 Proteins, Amino Acid Sequence, Animals, COS Cells, Cell Adhesion, Cell Line, Cytoskeleton, Gene Expression Regulation, Enzymologic, Glutathione Transferase, Hela Cells, Humans, Immunoblotting, Integrins, Microscopy, Fluorescence, Models, Biological, Molecular Sequence Data, Multigene Family, Plasmids, Precipitin Tests, Protein Binding, Protein-Serine-Threonine Kinases, Recombinant Fusion Proteins, Serine, Signal Transduction, Transfection, Two-Hybrid System Techniques, Tyrosine 3-Monooxygenase
J. Biol. Chem.
Date: Nov. 16, 2001
PubMed ID: 11555644
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