Fig. (2) Casp8p41 acts on mitochondria to release cytochrome c. (A) Jurkat cells cytosolic extracts containing (+) or lacking (-) mitochondria were analyzed by Western blot for Hsp70 and cytochrome c to confirmed the purity of the fractions. (B) Cytosolic extracts containing or lacking mitochondria were incubated with GST alone, GST casp8p41, or with recombinant caspase 8 for 2 hours. Release of cytochrome c into the cytosol and cleavage of caspase 9 were analyzed by Western blot.