title: Somatic Mutations in Catalytic Core of POLK Reported in Prostate Cancer Alter Translesion DNA Synthesis.
abstract: DNA polymerase kappa is a Y-family polymerase that participates to bypass the damaged DNA known as translesion synthesis (TLS) polymerase. Higher frequency of mutations in DNA polymerase kappa (POLK) recently been reported in prostate cancer. We sequenced entire exons of the POLK gene on genomic DNA from 40 prostate cancers and matched normal samples. We identified that 28% of patients have somatic mutations in the POLK gene of the prostate tumors. Mutations in these prostate cancers have somatic mutation spectra, which are dominated by C-to-T transitions. In the current study, we further investigate the effect of p.E29K, p.G154E, p.F155S, p.E430K, p.L442F, and p.E449K mutations on the biochemical properties of the polymerase in vitro, using TLS assay and nucleotide incorporation fidelity, following site-directed mutagenesis bacterial expression, and purification of the respective polymerase variants. We report that following missense mutations p.E29K, p.G154E, p.F155S, p.E430K, and p.L442F significantly diminished the catalytic efficiencies of POLK with regard to the lesion bypass (AP site). POLK variants show extraordinarily low fidelity by misincorporating T, C, and G as compared to wild-type variants. Taken together, these results suggest that interfering with normal polymerase kappa function by these mutations may be involved in prostate carcinogenesis.
authors.affiliation: Tulane Cancer Center, Tulane University, New Orleans, Louisiana.|Nephrology, Tulane University, New Orleans, Louisiana.
authors.forename: Santosh
authors.initials: S
authors.lastname: Yadav
authors.affiliation: Tulane Cancer Center, Tulane University, New Orleans, Louisiana.
authors.forename: Sudurkia
authors.initials: S
authors.lastname: Mukhopadhyay
authors.affiliation: Structural and Cellular Biology, Tulane University, New Orleans, Louisiana.
authors.forename: Muralidharan
authors.initials: M
authors.lastname: Anbalagan
authors.affiliation: Tulane Cancer Center, Tulane University, New Orleans, Louisiana.
authors.forename: Nick
authors.initials: N
authors.lastname: Makridakis
mesh_terms: D000368:Aged; D001482:Base Composition; D016022:Case-Control Studies; D002384:Catalysis; D020134:Catalytic Domain / Q000235:genetics*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004789:Enzyme Activation; D005091:Exons; D015870:Gene Expression; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D008958:Models, Molecular; D009154:Mutation; D060787:Neoplasm Grading; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D011487:Protein Conformation; D000099270:Y-Family DNA Polymerases
chemical_list: D004259:DNA-Directed DNA Polymerase; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases
keywords: catalytic efficiencies; missense mutations; polymerase kappa; prostate cancer; translesion synthesis