The Ku70/80 ring in Non-Homologous End-joining: Easy to slip on, hard to remove

Birthe B. Kragelund, Eric Weterings, Rasmus Hartmann-Petersen, Guido Keijzers

Research output: Contribution to journalReview articlepeer-review

30 Scopus citations


Non-homologous end-joining (NHEJ) is an essential DNA double strand break repair pathway during all cell cycle stages. Deficiency in NHEJ factors can lead to accumulation of unrepaired DNA breaks or faulty DNA repair, which may ultimately result in cell death, senescence or carcinogenesis. The Ku70/80 heterodimer is a key-player in the NHEJ pathway and binds to DNA termini with high affinity, where it helps to protect DNA ends from degradation and to recruit other NHEJ factors required for repair. The mechanism of Ku70/80 detachment from the DNA helix after completion of DNA repair is incompletely understood. Some data suggest that certain DNA repair factors are ubiquitylated and targeted for proteasomal degradation after repair. Recent studies suggest that Ku80 is conjugated to lysine48-linked ubiquitin chains by the Skp1-Cullin-F-box (SCF) complex and/or the RING finger protein 8 (RNF8) ubiquitin-protein ligases, followed by rapid proteasomal degradation. In this review we address the structure and function of the Ku70/80 heterodimer and how ubiquitylation may affect the release of Ku70/80 from chromatin and its subsequent degradation via the ubiquitin-proteasome system.

Original languageEnglish (US)
Pages (from-to)514-527
Number of pages14
JournalFrontiers in Bioscience - Landmark
Issue number3
StatePublished - Jan 1 2016


  • Degradation
  • Double strand break
  • Ku70
  • Ku80
  • NEDD8
  • NHEJ
  • Non-homologous endjoining
  • Proteasome
  • RNF8
  • Review
  • SCF
  • Ubiquitylation

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology


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