Histone H2AX participates the DNA damage-induced ATM activation through interaction with NBS1.
Phosphorylated histone H2AX (gamma-H2AX) functions in the recruitment of DNA damage response proteins to DNA double-strand breaks (DSBs) and facilitates DSB repair. ATM also co-localizes with gamma-H2AX at DSB sites following its auto-phosphorylation. However, it is unclear whether gamma-H2AX has a role in activation of ATM-dependent cell cycle checkpoints. Here, we show that ATM as well as NBS1 is recruited to damaged-chromatin in a gamma-H2AX-dependent manner. Foci formation of phosphorylated ATM and ATM-dependent phosphorylation is repressed in H2AX-knockdown cells. Furthermore, anti-gamma-H2AX antibody co-immunoprecipitates an ATM-like protein kinase activity in vitro and recombinant H2AX increases in vitro kinase activity of ATM from un-irradiated cells. Moreover, H2AX-deficient cells exhibited a defect in ATM-dependent cell cycle checkpoints. Taken together, gamma-H2AX has important role for effective DSB-dependent activation of ATM-related damage responses via NBS1.
Kobayashi
Junya
J
Department of Genome Repair Dynamics, Radiation Biology Center, Kyoto University, Kyoto 606-8501, Japan. jkobayashi@house.rbc.kyoto-u.ac.jp
Tauchi
Hiroshi
H
Chen
Benjamin
B
Burma
Sandeep
S
Bruma
Sandeep
S
Tashiro
Satoshi
S
Matsuura
Shinya
S
Tanimoto
Keiji
K
Chen
David J
DJ
Komatsu
Kenshi
K