A caspase homolog keeps CED-3 in check.

Apoptosis is a highly conserved form of cell death that is essential for controlling cell numbers throughout the lifetime of an organism. In Caenorhabditis elegans, the final step in the apoptotic cascade is activation of the death-inducing protease CED-3. Until now, no direct negative regulators of CED-3 had been identified, so the mechanism for maintaining a proper life-death balance was unclear. Now, a new study identifies CSP-3 as an important negative regulator of CED-3 during C. elegans development.