Abstract
Cyclin-dependent kinase 4 (CDK4)/cyclin D has a key role in regulating progression through late G(1) into S phase of the cell cycle. CDK4-cyclin D complexes then persist through the latter phases of the cell cycle, although little is known about their potential roles. We have developed small molecule inhibitors that are highly selective for CDK4 and have used these to define a role for CDK4-cyclin D in G(2) phase. The addition of the CDK4 inhibitor or small interfering RNA knockdown of cyclin D3, the cyclin D partner, delayed progression through G(2) phase and mitosis. The G(2) phase delay was independent of ATM/ATR and p38 MAPK but associated with elevated Wee1. The mitotic delay was because of failure of chromosomes to migrate to the metaphase plate. However, cells eventually exited mitosis, with a resultant increase in cells with multiple or micronuclei. Inhibiting CDK4 delayed the expression of the chromosomal passenger proteins survivin and borealin, although this was unlikely to account for the mitotic phenotype. These data provide evidence for a novel function for CDK4-cyclin D3 activity in S and G(2) phase that is critical for G(2)/M progression and the fidelity of mitosis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Caffeine / pharmacology
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Cell Cycle
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Cell Cycle Proteins / metabolism
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Cell Line
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Cell Proliferation
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Cyclin-Dependent Kinase 4 / chemistry*
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Cyclin-Dependent Kinase 4 / metabolism
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DNA, Complementary / metabolism
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Enzyme Inhibitors / pharmacology
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G1 Phase
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G2 Phase
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HeLa Cells
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Humans
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Imidazoles / pharmacology
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Inhibitor of Apoptosis Proteins
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Inhibitory Concentration 50
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Kinetics
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Microtubule-Associated Proteins / metabolism
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Mitosis
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Models, Chemical
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Neoplasm Proteins / metabolism
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Phenotype
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Phosphorylation
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Protein Binding
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Proto-Oncogene Proteins c-akt / metabolism
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Pyridines / pharmacology
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RNA / chemistry
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RNA, Small Interfering / metabolism
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Retinoblastoma Protein / metabolism
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Reverse Transcriptase Polymerase Chain Reaction
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S Phase
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Survivin
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Time Factors
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p38 Mitogen-Activated Protein Kinases / metabolism
Substances
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BIRC5 protein, human
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CDCA8 protein, human
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Cell Cycle Proteins
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DNA, Complementary
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Enzyme Inhibitors
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Imidazoles
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Inhibitor of Apoptosis Proteins
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Microtubule-Associated Proteins
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Neoplasm Proteins
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Pyridines
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RNA, Small Interfering
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Retinoblastoma Protein
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Survivin
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Caffeine
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RNA
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Proto-Oncogene Proteins c-akt
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Cyclin-Dependent Kinase 4
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p38 Mitogen-Activated Protein Kinases
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SB 203580