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, YuanYu
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 - 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
SN - 1074-5521
VL - 22
SP - 849
EP - 861
JO - Chemistry and Biology
JF - Chemistry and Biology
IS - 7
M1 - 3066
ER -