TY - JOUR
T1 - A conserved Ctp1/CtIP C-terminal peptide stimulates Mre11 endonuclease activity
AU - Zdravković, Aleksandar
AU - Daley, James M.
AU - Dutta, Arijit
AU - Niwa, Tatsuya
AU - Murayama, Yasuto
AU - Kanamaru, Shuji
AU - Ito, Kentaro
AU - Maki, Takahisa
AU - Argunhan, Bilge
AU - Takahashi, Masayuki
AU - Tsubouchi, Hideo
AU - Sung, Patrick
AU - Iwasaki, Hiroshi
N1 - Funding Information:
ACKNOWLEDGMENTS. We thank Yumiko Kurokawa for help with protein purification and members of the H.I. laboratory for discussion and encouragement. This study was supported in part by the Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research on Innovative Areas (15H059749 to H.I.), for Scientific Research (A) (18H03985 to H.I.), for Young Scientists (B) (17K15061 to B.A.), for Scientific Research (B) (18H02371 to H.T. and 19H03160 to Y.M.), for Early-Career Scientists (19K16039 to K.I. and 20K15713 to B.A.), and by NIH Grant R35 CA241801 (to P.S.).
Publisher Copyright:
© 2021 National Academy of Sciences. All rights reserved.
PY - 2021/3/16
Y1 - 2021/3/16
N2 - The Mre11-Rad50-Nbs1 complex (MRN) is important for repairing DNA double-strand breaks (DSBs) by homologous recombination (HR). The endonuclease activity of MRN is critical for resecting 5′- ended DNA strands at DSB ends, producing 3′-ended single-strand DNA, a prerequisite for HR. This endonuclease activity is stimulated by Ctp1, the Schizosaccharomyces pombe homolog of human CtIP. Here, with purified proteins, we show that Ctp1 phosphorylation stimulatesMRN endonuclease activity by inducing the association of Ctp1 with Nbs1. The highly conserved extreme C terminus of Ctp1 is indispensable for MRN activation. Importantly, a polypeptide composed of the conserved 15 amino acids at the C terminus of Ctp1 (CT15) is sufficient to stimulate Mre11 endonuclease activity. Furthermore, the CT15 equivalent from CtIP can stimulate human MRE11 endonuclease activity, arguing for the generality of this stimulatory mechanism. Thus, we propose that Nbs1-mediated recruitment of CT15 plays a pivotal role in the activation of the Mre11 endonuclease by Ctp1/CtIP.
AB - The Mre11-Rad50-Nbs1 complex (MRN) is important for repairing DNA double-strand breaks (DSBs) by homologous recombination (HR). The endonuclease activity of MRN is critical for resecting 5′- ended DNA strands at DSB ends, producing 3′-ended single-strand DNA, a prerequisite for HR. This endonuclease activity is stimulated by Ctp1, the Schizosaccharomyces pombe homolog of human CtIP. Here, with purified proteins, we show that Ctp1 phosphorylation stimulatesMRN endonuclease activity by inducing the association of Ctp1 with Nbs1. The highly conserved extreme C terminus of Ctp1 is indispensable for MRN activation. Importantly, a polypeptide composed of the conserved 15 amino acids at the C terminus of Ctp1 (CT15) is sufficient to stimulate Mre11 endonuclease activity. Furthermore, the CT15 equivalent from CtIP can stimulate human MRE11 endonuclease activity, arguing for the generality of this stimulatory mechanism. Thus, we propose that Nbs1-mediated recruitment of CT15 plays a pivotal role in the activation of the Mre11 endonuclease by Ctp1/CtIP.
KW - Ctp1/CtIP
KW - Double-strand break repair
KW - Fission yeast
KW - Homologous recombination
KW - Mre11-Rad50-Nbs1
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U2 - 10.1073/pnas.2016287118
DO - 10.1073/pnas.2016287118
M3 - Article
C2 - 33836577
AN - SCOPUS:85102375031
VL - 118
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 11
M1 - e2016287118
ER -