Figure 5. NBS1 Ubiquitination Is Critical for ATM Activation and Recruitment.
(A) 293T cells were transfected with indicated plasmids and harvested for in vivo ubiquitination assay.
(B) 293 cells transfected with Flag-NBS1 WT, K735R, and K751R respectively were treated with IR (3 Gy) and harvested for western blot analysis 5 min after IR treatment.
(C) 293 cells were transfected with Flag-NBS1 WT, K735R, and K751R, respectively, treated with or without IR (10 Gy), and harvested for the isolation of chromatin fraction 5 min after IR, followed by western blot analysis.
(D) HeLa cells transfected with WT-NBS1 and NBS1-K735R were treated with IR (3 Gy) and harvested for IF analysis 5 min after IR treatment. Percentages of cells with positive ATM-s1981p foci were quantified from cells with positive Flag-NBS1 transfection. Results are presented as mean values ± standard deviation (SD) from three different experiments.
(E) 293 cells were transfected with Flag-NBS1 WT and K735R, respectively, treated with IR (3 Gy), and harvested for coimmunoprecipitation assay at various time points, followed by western blot analysis.