Role of SUMO:SIM-mediated protein-protein interaction in non-homologous end joining

Y. J. Li, J. M. Stark, D. J. Chen, D. K. Ann, Y. Chen

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Although post-translational modifications by the small ubiquitin-like modifiers (SUMO) are known to be important in DNA damage response, it is unclear whether they have a role in double-strand break (DSB) repair by non-homologous end joining (NHEJ). Here, we analyzed various DSB repair pathways upon inhibition of SUMO-mediated protein-protein interactions using peptides that contain the SUMO-interaction motif (SIM) and discriminate between mono-and SUMO-chain modifications. The SIM peptides specifically inhibit NHEJ as shown by in vivo repair assays and radio-sensitivity of cell lines deficient in different DSB repair pathways. Furthermore, mono-SUMO, instead of SUMO-chain, modifications appear to be involved in NHEJ. Immunoprecipitation experiments also showed that the SIM peptide interacted with SUMOylated Ku70 after radiation. This study is the first to show an important role for SUMO:SIM-mediated protein-protein interactions in NHEJ, and provides a mechanistic basis for the role of SIM peptide in sensitizing genotoxic stress of cancer cells.

Original languageEnglish (US)
Pages (from-to)3509-3518
Number of pages10
Issue number24
StatePublished - Jun 17 2010


  • DNA repair
  • Inhibitor
  • NHEJ
  • SBM
  • SUMO
  • SUMO-interacting motif

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research


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