Sarm-Assisted Suicide Neurodegenerative disease or nerve lesions cause axons and synapses to disintegrate through a process known as Wallerian degeneration, which may involve an active “axon death program.” Osterloh et al. (p. 481 , published online 7 June; see the Perspective by Yu and Luo ) identify loss-of-function mutations in Drosophila dSarm that are capable of blocking the degeneration of severed axons for the fly life span. Deletion of mouse Sarm1 provides similar protection to severed axons for weeks after injury, which suggests that Sarm is part of an ancient axonal death signaling cascade.