(a) Raf-1-mediated protection of caspase 9 cleavage requires protein synthesis. CCL39-Raf-1:ER cells were deprived of serum for a total time of 24 hours in the presence or absence of 1 M 4-HT. The protein synthesis inhibitor emetine (20 M) was added at the indicated time point. The cell lysates were analyzed by immunoblotting for caspase-9, phospho-MAPK1,3, total MAPK1 and XIAP. (b) and (c) time course of Raf-1-mediated caspase 9 inhibition. (b) CCL39-Raf-1:ER cells were deprived of serum for a total time of 24 hours in the presence of 50 nM 4-HT. 10 M U0126 was added at the indicated time after serum withdrawal. (c) Cells were deprived of serum for 24 h; 4-HT (1 M) was added at the indicated time after serum withdrawal. The cell lysates were analyzed by immunoblotting for caspase-9.