ICE-related proteases in apoptosis.

Apoptotic execution involves numerous enzymatic pathways, all of which appear to be triggered by the activation of one or more ICE-related proteases (IRPs). Considerable effort is currently being expended in the identification and functional characterization of the rapidly expanding superfamily of IRPs. Important questions that remain unsolved include the identity of the vertebrate IRP that triggers the apoptotic cascade and the identities of the crucial substrates whose cleavage results in the dramatic morphological changes during apoptosis.