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Nature. 2017 Mar 9;543(7644):211-216. doi: 10.1038/nature21358. Epub 2017 Feb 27.

TIRR regulates 53BP1 by masking its histone methyl-lysine binding function.

Author information

1
Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
2
Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA.
3
Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch 67404, France.
4
Immunology Program, Memorial Sloan-Kettering Cancer Center, Gerstner Sloan-Kettering Graduate School, New York, New York 10065, USA.
5
Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
6
Immunology and Microbial Pathogenesis Program, Weill-Cornell Medical School, New York, New York 10065, USA.
7
Department of Biological Chemistry &Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
8
Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA.

Abstract

P53-binding protein 1 (53BP1) is a multi-functional double-strand break repair protein that is essential for class switch recombination in B lymphocytes and for sensitizing BRCA1-deficient tumours to poly-ADP-ribose polymerase-1 (PARP) inhibitors. Central to all 53BP1 activities is its recruitment to double-strand breaks via the interaction of the tandem Tudor domain with dimethylated lysine 20 of histone H4 (H4K20me2). Here we identify an uncharacterized protein, Tudor interacting repair regulator (TIRR), that directly binds the tandem Tudor domain and masks its H4K20me2 binding motif. Upon DNA damage, the protein kinase ataxia-telangiectasia mutated (ATM) phosphorylates 53BP1 and recruits RAP1-interacting factor 1 (RIF1) to dissociate the 53BP1-TIRR complex. However, overexpression of TIRR impedes 53BP1 function by blocking its localization to double-strand breaks. Depletion of TIRR destabilizes 53BP1 in the nuclear-soluble fraction and alters the double-strand break-induced protein complex centring 53BP1. These findings identify TIRR as a new factor that influences double-strand break repair using a unique mechanism of masking the histone methyl-lysine binding function of 53BP1.

PMID:
28241136
PMCID:
PMC5441565
DOI:
10.1038/nature21358
[Indexed for MEDLINE]
Free PMC Article

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