XRCC1 stimulates human polynucleotide kinase activity at damaged DNA termini and accelerates DNA single-strand break repair

Cell. 2001 Jan 12;104(1):107-17. doi: 10.1016/s0092-8674(01)00195-7.


XRCC1 protein is required for DNA single-strand break repair and genetic stability but its biochemical role is unknown. Here, we report that XRCC1 interacts with human polynucleotide kinase in addition to its established interactions with DNA polymerase-beta and DNA ligase III. Moreover, these four proteins are coassociated in multiprotein complexes in human cell extract and together they repair single-strand breaks typical of those induced by reactive oxygen species and ionizing radiation. Strikingly, XRCC1 stimulates the DNA kinase and DNA phosphatase activities of polynucleotide kinase at damaged DNA termini and thereby accelerates the overall repair reaction. These data identify a novel pathway for mammalian single-strand break repair and demonstrate a concerted role for XRCC1 and PNK in the initial step of processing damaged DNA ends.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CHO Cells
  • Cricetinae
  • DNA Damage / physiology
  • DNA Ligase ATP
  • DNA Ligases / genetics
  • DNA Ligases / metabolism
  • DNA Polymerase beta / genetics
  • DNA Polymerase beta / metabolism
  • DNA Repair / physiology*
  • DNA, Single-Stranded / genetics
  • DNA, Single-Stranded / metabolism
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism*
  • Enzyme Activation / genetics
  • Humans
  • Phosphoric Monoester Hydrolases / genetics
  • Phosphoric Monoester Hydrolases / metabolism
  • Poly-ADP-Ribose Binding Proteins
  • Polynucleotide 5'-Hydroxyl-Kinase / genetics*
  • Polynucleotide 5'-Hydroxyl-Kinase / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • X-ray Repair Cross Complementing Protein 1
  • Xenopus Proteins
  • Yeasts


  • DNA, Single-Stranded
  • DNA-Binding Proteins
  • Poly-ADP-Ribose Binding Proteins
  • Recombinant Proteins
  • X-ray Repair Cross Complementing Protein 1
  • XRCC1 protein, human
  • Xenopus Proteins
  • Polynucleotide 5'-Hydroxyl-Kinase
  • DNA Polymerase beta
  • Phosphoric Monoester Hydrolases
  • DNA Ligases
  • DNA Ligase ATP
  • DNA ligase III alpha protein, Xenopus
  • LIG3 protein, human