Caspase activation without death.

Since molecular cloning of the C. elegans ced-3 gene revealed its homology with mammalian IL-1beta-converting enzyme,1 14 members of the caspase family have been identified, which have often been involved as mediators of one or more phases of the apoptotic process. 2,3 However, an over-simplified role of these proteases may be insufficient to explain the usually constitutive expression of such a large and complex family of enzymes, many of which display overlapping specificity. In addition to the well-established role of caspase-1 in the production of active IL-1beta and IL-18 in inflammation,4 an increasing number of reports has recently suggested that caspases may have a function outside of apoptosis. In this review, the situations in which cells survive despite the presence of activated caspases in their cytoplasm will be examined and discussed, with the intent to gather all recent advances in this new field that promises to be a focus for caspase research in the near future.