TIRR inhibits the 53BP1-p53 complex to alter cell-fate programs

Nishita Parnandi, Veronica Rendo, Gaofeng Cui, Maria Victoria Botuyan, Michaela Remisova, Huy Nguyen, Pascal Drané, Rameen Beroukhim, Matthias Altmeyer, Georges Mer, Dipanjan Chowdhury

Research output: Contribution to journalArticlepeer-review


53BP1 influences genome stability via two independent mechanisms: (1) regulating DNA double-strand break (DSB) repair and (2) enhancing p53 activity. We discovered a protein, Tudor-interacting repair regulator (TIRR), that associates with the 53BP1 Tudor domain and prevents its recruitment to DSBs. Here, we elucidate how TIRR affects 53BP1 function beyond its recruitment to DSBs and biochemically links the two distinct roles of 53BP1. Loss of TIRR causes an aberrant increase in the gene transactivation function of p53, affecting several p53-mediated cell-fate programs. TIRR inhibits the complex formation between the Tudor domain of 53BP1 and a dimethylated form of p53 (K382me2) that is poised for transcriptional activation of its target genes. TIRR mRNA expression levels negatively correlate with the expression of key p53 target genes in breast and prostate cancers. Further, TIRR loss is selectively not tolerated in p53-proficient tumors. Therefore, we establish that TIRR is an important inhibitor of the 53BP1-p53 complex.

Original languageEnglish (US)
Pages (from-to)2583-2595.e6
JournalMolecular Cell
Issue number12
StatePublished - Jun 17 2021


  • 53BP1
  • NMR
  • TIRR
  • Tudor
  • cancer
  • cell fate
  • p53
  • senescence
  • survival
  • transcription factor

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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