To explore if DNA-PKcs might also execute radiation-induced Akt-S473 phosphorylation in intact cancer cells, we analyzed the time-dependent phosphorylation of Akt-S473 in irradiated DNA-PKcs-deficient (M059J) and DNA-PKcs-proficient (M059K) human glioblastoma cell lines (Figure 1; Figure S1A). Here, AKT1 is linked to glioblastoma.