Transducing signals of life and death.

The molecules that form signaling complexes with the cytoplasmic domains of tumor necrosis factor (TNF) receptors (TNF-Rs) and CD95 have been identified recently. The death-signaling pathways induced by TNF-R1 and CD95 involve a group of death domain containing proteins, including caspase-8, a member of the interleukin-1beta-converting enzyme family. TNF-R1 and TNF-R2 also interact with the members of both the TNF-R associated factor family and the inhibitor of apoptosis protein family; these interactions lead to cell survival.