Fig. 3.
Effect of ATRA on the phosphorylation of pRB. Whole-cell extracts from control and cells treated with 10−6 mol/L ATRA for 48 and 72 hours were immunoprecipitated with anti-RB antibody. The immunoprecipitates were analyzed by Western blot and probed with a second anti-RB antibody. The phosphorylated (p-RB) and dephosphorylated retinoblastoma protein (RB) bands were as indicated.