(a) and (b): Raf-1 activity does not interfere with apoptosome formation. CCL39-Raf-1:ER cells growing in 7.5% FCS (control) were deprived of serum () for 14 hours in the presence or absence of 4-HT. The lysates were separated by gel filtration chromatography on a sephacryl S300 column previously calibrated with the indicated molecular weight standards. Samples from high molecular weight fractions were diluted with 4X Laemmli buffer and were analyzed by immunoblotting for the presence of APAF-1 (a) and cytochrome c (b). (c) and (d): recruitment of caspase 9 in the apoptosome. (c) The conditions are the same as in Figures 7(a) and 7(b); samples are a pool of 2 fractions and were analyzed by immunoblotting for caspase 9. pro: procaspase 9, 47 kd. p37, p35: cleaved caspase 9. (d) Recruitment of caspase 9 in high molecular weight fractions. Detailed analysis of high molecular weight fractions from Figure 7(c).