DDB1 mediates UV irradiation-induced GRK5 degradation.

<p>(A) 293 T cells were treated with 20, 100 or 300 J/m² of UV-C irradiation. One or two hours after UV treatment, cells were harvested and analyzed by Western blotting with antibodies specific for the indicated proteins. (B) 293 T cells were incubated for 0, 5, 15, 30, 60, or 120 min after 20 J/m² UV-C irradiation, and then cells were harvested and analyzed by Western blotting with antibodies specific for the indicated proteins. Quantitative graphs are shown. The amount of GRK5 at 0 h was defined as 100%. Data are the mean±SE from 4 independent experiments. (C) 293 T cells were infected by lentivirus encoding control or DDB1 RNAi. After 72 h, cells were treated with 20 J/m² UV-C irradiation, and then incubated for the indicated time. Cells were harvested and analyzed by Western blotting. (D) 293 T cells were pretreated with or without isoproterenol (1 µM) for 20 min before 20 J/m² UV-C irradiation, and then incubated in the presence or absence of isoproterenol (1 µM) for the indicated time. Cells were harvested and analyzed by Western blotting.