Abstract
Aurora family kinases contribute to regulation of mitosis. Using RNA interference in synchronized HeLa cells, we now show that Aurora-A is required for mitotic entry. We found that initial activation of Aurora-A in late G2 phase of the cell cycle is essential for recruitment of the cyclin B1-Cdk1 complex to centrosomes, where it becomes activated and commits cells to mitosis. A two-hybrid screen identified the LIM protein Ajuba as an Aurora-A binding protein. Ajuba and Aurora-A interact in mitotic cells and become phosphorylated as they do so. In vitro analyses revealed that Ajuba induces the autophosphorylation and consequent activation of Aurora-A. Depletion of Ajuba prevented activation of Aurora-A at centrosomes in late G2 phase and inhibited mitotic entry. Overall, our data suggest that Ajuba is an essential activator of Aurora-A in mitotic commitment.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Aurora Kinase A
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Aurora Kinases
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CDC2 Protein Kinase / metabolism
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COS Cells
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Cell Cycle
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Cell Cycle Proteins
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Cell Line
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Centrosome / ultrastructure
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Cyclin B / metabolism
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Cyclin B1
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G2 Phase
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Gene Deletion
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Glutathione Transferase / metabolism
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HeLa Cells
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Homeodomain Proteins / metabolism
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Homeodomain Proteins / physiology*
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Humans
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LIM Domain Proteins
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Microscopy, Fluorescence
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Mitosis*
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Models, Biological
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Molecular Sequence Data
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Phosphorylation
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Precipitin Tests
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Protein Binding
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Protein Kinases / metabolism
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Protein Kinases / physiology*
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Protein Serine-Threonine Kinases
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RNA Interference
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Recombinant Proteins / metabolism
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Temperature
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Time Factors
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Two-Hybrid System Techniques
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Xenopus Proteins
Substances
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AJUBA protein, human
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Ajuba protein, rat
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CCNB1 protein, human
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Ccnb1 protein, rat
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Cell Cycle Proteins
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Cyclin B
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Cyclin B1
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Homeodomain Proteins
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LIM Domain Proteins
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Recombinant Proteins
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Xenopus Proteins
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Glutathione Transferase
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Protein Kinases
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AURKA protein, Xenopus
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Aurka protein, rat
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Aurora Kinase A
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Aurora Kinases
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Protein Serine-Threonine Kinases
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CDC2 Protein Kinase