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 bereversed by inhibiting nonhomologous end-joining. We also reveal that protein phosphatase complex PP4C/R3β dephosphorylates T1609 and S1618 toallow 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.
Original language | English |
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Pages (from-to) | 512-525 |
Number of pages | 14 |
Journal | Molecular Cell |
Volume | 54 |
Issue number | 3 |
DOIs | |
State | Published - 8 May 2014 |
Bibliographical note
Funding Information:The 53BP1 −/− MEFs and the 53BP1-GFP siRNA-resistant construct were gifts from P. Jeggo (Sussex). The GFP-RNF168-expressing U2OS cells and modified nuclesomes core particles (NCPs) were a gift from D. Durocher (Toronto). Human CREST serum was a gift from Dr. Arno Kromminga. Thanks to Xiao-Feng Zheng for making the graphical abstract. D.C. is supported by R01CA142698 (NCI), R01 AI101897-01 (NIAID), Basic Scholar Grant (American Cancer Society), Ann-Fuller Foundation, Mary Kay Foundation, and start-up funds from DFCI. D.-H.L. is supported by Basic Science Research Program through the National Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2013R1A1A1061207), and Chonnam National University, 2013.