The protein encoded by this gene is a regulator of apoptosis and is structurally similar to caspase-8. However, the encoded protein lacks caspase activity and appears to be itself cleaved into two peptides by caspase-8. Several transcript variants encoding different isoforms have been found for this gene, and partial evidence for several more variants exists. [provided by RefSeq, Feb 2011],domain:The caspase domain lacks the active sites residues involved in catalysis.,function:Apoptosis regulator protein which may function as a crucial link between cell survival and cell death pathways in mammalian cells. Acts as an inhibitor of TNFRSF6 mediated apoptosis. A proteolytic fragment (p43) is likely retained in the death-inducing signaling complex (DISC) thereby blocking further recruitment and processing of caspase-8 at the complex. Full length and shorter isoforms have been shown either to induce apoptosis or to reduce TNFRSF-triggered apoptosis. Lacks enzymatic (caspase) activity.,induction:Repressed by IL-2 after TCR stimulation, during progression to the S-phase of the cell cycle.,PTM:Proteolytically processed; probably by caspase-8. Processing likely occurs at the DISC and generates subunit p43 and p12.,similarity:Belongs to the peptidase C14A family.,similarity:Contains 2 DED (death effector) domains.,subunit:TNFRSF6 stimulation triggers recruitment to the death-inducing signaling complex (DISC) formed by TNFRSF6, FADD and caspase-8. A proteolytic fragment (p43) stays associated with the DISC. Also interacts with caspase-10, caspase-3, TRAF1, TRAF2 and Bcl-X(L) (in vitro). Interacts with HBV protein X.,tissue specificity:Widely expressed. Higher expression in skeletal muscle, pancreas, heart, kidney, placenta, and peripheral blood leukocytes. Also detected in diverse cell lines. Isoform 8 is predominantly expressed in testis and skeletal muscle.,