Abstract
The capacity of the cyclin D-dependent kinase to promote G(1) progression through modulation of RB.E2F is well documented. We now demonstrate that the cyclin D1/CDK4 kinase binds to components of the MCM complex. MCM7 and MCM3 were identified as cyclin D1-binding proteins. Catalytically active cyclin D1/CDK4 complexes were incorporated into chromatin-bound protein complexes with the same kinetics as MCM7 and MCM3, where they associated specifically with MCM7. Although the cyclin D1-dependent kinase did not phosphorylate MCM7, active cyclin D1/CDK4, but not cyclin E/CDK2, did catalyze the dissociation of an RB.MCM7 complex. Finally, expression of an active D1/CDK4 kinase but not cyclin E/CDK2 promoted the removal of RB from chromatin-bound protein complexes. Our data suggest that D1/CDK4 complexes play a direct role in altering an inhibitory RB.MCM7 complex possibly allowing for setting of the origin in preparation for DNA replication.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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3T3 Cells
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Animals
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Catalysis
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Cell Cycle Proteins / metabolism*
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Cell Line
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Chromatin / metabolism
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Cyclin D
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Cyclin D1 / metabolism*
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Cyclin-Dependent Kinase 4
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Cyclin-Dependent Kinases / metabolism*
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Cyclins / metabolism
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DNA, Complementary / metabolism
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DNA-Binding Proteins / metabolism*
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Insecta
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Kinetics
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Mice
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Microscopy, Fluorescence
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Minichromosome Maintenance Complex Component 7
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Nuclear Proteins / metabolism*
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Phosphorylation
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Precipitin Tests
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Protein Binding
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Protein Structure, Tertiary
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Proto-Oncogene Proteins*
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Retinoblastoma Protein / metabolism*
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Time Factors
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Transfection
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Two-Hybrid System Techniques
Substances
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Cell Cycle Proteins
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Chromatin
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Cyclin D
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Cyclins
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DNA, Complementary
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DNA-Binding Proteins
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Nuclear Proteins
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Proto-Oncogene Proteins
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Retinoblastoma Protein
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Cyclin D1
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Cdk4 protein, mouse
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Cyclin-Dependent Kinase 4
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Cyclin-Dependent Kinases
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Mcm7 protein, mouse
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Minichromosome Maintenance Complex Component 7