TY - JOUR
T1 - Non-canonical Bromodomain within DNA-PKcs Promotes DNA Damage Response and Radioresistance through Recognizing an IR-Induced Acetyl-Lysine on H2AX
AU - Wang, Li
AU - Xie, Ling
AU - Ramachandran, Srinivas
AU - Lee, Yuan Yu
AU - Yan, Zhen
AU - Zhou, Li
AU - Krajewski, Krzysztof
AU - Liu, Feng
AU - Zhu, Cheng
AU - Chen, David J.
AU - Strahl, Brian D.
AU - Jin, Jian
AU - Dokholyan, Nikolay V.
AU - Chen, Xian
N1 - Funding Information:
This work is primarily supported in part by multiple grants to X.C. including Chinese 973 fund 2013CB910802, US NIH 1U24CA160035 from the National Cancer Institute Clinical Proteomic Tumor Analysis Consortium (CPTAC), and NIAID 1U19AI109965, and was also supported by NIH R01GM103893 (to J.J.), R01GM080742 (to N.V.D.), and R01CA162804 and R01CA92584 (to D.J.C). We thank William K. Kaufmann for providing ATM/mutant cell lines, and Dale A. Ramsden for suggestions. We are grateful to Dr. James E. Bradner for providing JQ1 and Dr. Howard Fried for proofreading the manuscript.
Publisher Copyright:
© 2015 Elsevier Ltd.
PY - 2015/7/24
Y1 - 2015/7/24
N2 - Summary Regulatory mechanisms underlying γH2AX induction and the associated cell fate decision during DNA damage response (DDR) remain obscure. Here, we discover a bromodomain (BRD)-like module in DNA-PKcs (DNA-PKcs-BRD) that specifically recognizes H2AX acetyl-lysine 5 (K5ac) for sequential induction of γH2AX and concurrent cell fate decision(s). First, top-down mass spectrometry of radiation-phenotypic, full-length H2AX revealed a radiation-inducible, K5ac-dependent induction of γH2AX. Combined approaches of sequence-structure modeling/docking, site-directed mutagenesis, and biochemical experiments illustrated that through docking on H2AX K5ac, this non-canonical BRD determines not only the H2AX-targeting activity of DNA-PKcs but also the over-activation of DNA-PKcs in radioresistant tumor cells, whereas a Kac antagonist, JQ1, was able to bind to DNA-PKcs-BRD, leading to re-sensitization of tumor cells to radiation. This study elucidates the mechanism underlying the H2AX-dependent regulation of DNA-PKcs in ionizing radiation-induced, differential DDR, and derives an unconventional, non-catalytic domain target in DNA-PKs for overcoming resistance during cancer radiotherapy.
AB - Summary Regulatory mechanisms underlying γH2AX induction and the associated cell fate decision during DNA damage response (DDR) remain obscure. Here, we discover a bromodomain (BRD)-like module in DNA-PKcs (DNA-PKcs-BRD) that specifically recognizes H2AX acetyl-lysine 5 (K5ac) for sequential induction of γH2AX and concurrent cell fate decision(s). First, top-down mass spectrometry of radiation-phenotypic, full-length H2AX revealed a radiation-inducible, K5ac-dependent induction of γH2AX. Combined approaches of sequence-structure modeling/docking, site-directed mutagenesis, and biochemical experiments illustrated that through docking on H2AX K5ac, this non-canonical BRD determines not only the H2AX-targeting activity of DNA-PKcs but also the over-activation of DNA-PKcs in radioresistant tumor cells, whereas a Kac antagonist, JQ1, was able to bind to DNA-PKcs-BRD, leading to re-sensitization of tumor cells to radiation. This study elucidates the mechanism underlying the H2AX-dependent regulation of DNA-PKcs in ionizing radiation-induced, differential DDR, and derives an unconventional, non-catalytic domain target in DNA-PKs for overcoming resistance during cancer radiotherapy.
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U2 - 10.1016/j.chembiol.2015.05.014
DO - 10.1016/j.chembiol.2015.05.014
M3 - Article
C2 - 26119999
AN - SCOPUS:84937812073
VL - 22
SP - 849
EP - 861
JO - Cell Chemical Biology
JF - Cell Chemical Biology
SN - 2451-9448
IS - 7
M1 - 3066
ER -
