Abstract
DNA polymerase delta (Pol δ) is a central enzyme for eukaryotic DNA replication and repair. Pol δ is a complex of four subunits p125, p68, p50, and p12. The functional properties of Pol δ are largely determined by its interaction with its DNA sliding clamp PCNA (proliferating cellular nuclear antigen). The regulatory mechanisms that govern the association of Pol δ with PCNA are largely unknown. In this study, we identified S458, located in the PCNA-interacting protein (PIP-Box) motif of p68, as a phosphorylation site for PKA. Phosphomimetic mutation of S458 resulted in a decrease in p68 affinity for PCNA as well as the processivity of Pol δ. Our results suggest a role of phosphorylation of the PIP-motif of p68 as a molecular switch that dynamically regulates the functional properties of Pol δ.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Motifs / genetics
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Amino Acid Sequence
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Aspartic Acid / genetics
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Cyclic AMP-Dependent Protein Kinases / chemistry
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Cyclic AMP-Dependent Protein Kinases / physiology
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DNA Polymerase III / antagonists & inhibitors
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DNA Polymerase III / chemistry*
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DNA Polymerase III / genetics
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Down-Regulation / genetics
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HeLa Cells
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Humans
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Molecular Mimicry / genetics
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Molecular Sequence Data
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Mutation
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Phosphorylation / genetics
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Proliferating Cell Nuclear Antigen / chemistry*
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Proliferating Cell Nuclear Antigen / genetics
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Proliferating Cell Nuclear Antigen / metabolism*
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Protein Binding / genetics
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Protein Processing, Post-Translational / genetics
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Protein Subunits / antagonists & inhibitors
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Protein Subunits / chemistry
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Protein Subunits / genetics
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Serine / genetics
Substances
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Proliferating Cell Nuclear Antigen
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Protein Subunits
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Aspartic Acid
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Serine
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Cyclic AMP-Dependent Protein Kinases
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DNA Polymerase III