B. MEFs were cultured for 12 h in medium containing 10 μg/ml FAC supplemented with DMSO or 10 μM E64d and 10 μg/ml pepstatin A (pepA). Samples were analyzed by immunoblotting with the indicated antibodies. The black arrowhead indicates an intact ferritin band, and the white arrowhead indicates a partial degradation band of ferritin. 