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Mol Cell. 2014 May 8;54(3):512-25. doi: 10.1016/j.molcel.2014.03.020. Epub 2014 Apr 3.

Dephosphorylation enables the recruitment of 53BP1 to double-strand DNA breaks.

Author information

1
Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Biological Sciences, College of Science, Chonnam National University, Gwangju 500-757, Republic of Korea.
2
Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
3
Department of Cell Biology, Harvard Medical School, Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Howard Hughes Medical Institute, Brigham and Women's Hospital, Boston, MA 02115, USA.
4
Department of Systems Biology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115, USA.
5
Department of Biological Chemistry Molecular Pharmacology, Harvard Medical School, Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
6
Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA. Electronic address: dipanjan_chowdhury@dfci.harvard.edu.

Abstract

Excluding 53BP1 from chromatin is required to attenuate the DNA damage response during mitosis, yet the functional relevance and regulation of this exclusion are unclear. Here we show that 53BP1 is phosphorylated during mitosis on two residues, T1609 and S1618, located in its well-conserved ubiquitination-dependent recruitment (UDR) motif. Phosphorylating these sites blocks the interaction of the UDR motif with mononuclesomes containing ubiquitinated histone H2A and impedes binding of 53BP1 to mitotic chromatin. Ectopic recruitment of 53BP1-T1609A/S1618A to mitotic DNA lesions was associated with significant mitotic defects that could be reversed by inhibiting nonhomologous end-joining. We also reveal that protein phosphatase complex PP4C/R3β dephosphorylates T1609 and S1618 to allow the recruitment of 53BP1 to chromatin in G1 phase. Our results identify key sites of 53BP1 phosphorylation during mitosis, identify the counteracting phosphatase complex that restores the potential for DDR during interphase, and establish the physiological importance of this regulation.

PMID:
24703952
PMCID:
PMC4030556
DOI:
10.1016/j.molcel.2014.03.020
[Indexed for MEDLINE]
Free PMC Article

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