P atm ser1981

Cells were transfected with expression plasmids using Lipofectamine 3000 (Invitrogen, CA, USA), and were exposed to γ-rays (5 Gy) as previously described.11 (link) Antibodies against phosphorylated cAMP response element bind protein (p-CREB, Ser139), phosphorylated ataxia telangiectasia-mutated protein (p-ATM, Ser1981), and the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) were obtained from Santa Cruz Biotechnology. Antibodies against p-H2AX (Ser133), phosphorylated PKA substrates, cleaved poly (ADP-ribose) polymerase (PARP), and cleaved caspase-9 were purchased from Cell Signaling Technology (Beverly, MA, USA). An antibody against β-actin was purchased from Sigma-Aldrich, and Antibodies against DNA-PKcs phosphorylated at Thr2609 (T2609) and Ser2056 (S2056) were purchased from Abcam (Cambridge, UK). The proteins were visualized using enhanced chemiluminescence (Thermo Fisher Scientific, Waltham, MA, USA), and the blot images were recorded using the LAS-3000 luminescent image analyzer (Fuji, Tokyo, Japan). The densities of the visualized bands were analyzed using Multi Gauge v.2.3 software (Olympus, Tokyo, Japan), and the band densities were expressed as ratios of the corresponding control densities.