Rehabilitation of a contract killer: Caspase-3 directs stem cell differentiation

Activation of caspase-3 is generally acknowledged as a penultimate step in apoptotic cell death pathways. Two studies in this issue of Cell Stem Cell (Fujita et al., 2008; Janzen et al., 2008) provide compelling data to demonstrate that caspase-3 is also a conserved inductive cue for stem cell differentiation.