ORDERING THE MULTIPLE PATHWAYS OF APOPTOSIS

Apoptosis plays an important role in development, homeostasis, and dis ease. Current work has suggested that apoptosis can be evoked by multi ple stimuli that, in turn, initiate distinct death pathways. Recently, exciting advances have been made in the understanding of biochemical pathways that regulate apoptotic processes. These pathways contain bot h evolutionarily conserved elements and components that are dependent on the death stimulus and cell context. Accordingly, this review focus es on the compositions and relative ordering of the apoptotic pathways in four different death paradigms: activation of receptor of the Fas ligand, destruction by cytotoxic T lymphocytes, exposure to DNA damagi ng agents, and loss of support by neurotrophic factors. These examples illustrate the conservation and divergence in the ways that death pat hways are composed and ordered. (C) 1997, Elsevier Science Inc.