Phosphorylation of the p68 subunit of Pol delta acts as a molecular switch to regulate its interaction with PCNA.
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Rahmeh AA, Zhou Y, Xie B, Li H, Lee EY, Lee MY
Phosphorylation of the p68 subunit of Pol delta acts as a molecular switch to regulate its interaction with PCNA.
Biochemistry. 2012 Jan 10;51(1):416-24. doi: 10.1021/bi201638e. Epub 2011 Dec 20.
- PubMed ID
- 22148433 [ View in PubMed]
- Abstract
DNA polymerase delta (Pol delta) is a central enzyme for eukaryotic DNA replication and repair. Pol delta is a complex of four subunits p125, p68, p50, and p12. The functional properties of Pol delta 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 delta 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 delta. 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 delta.