Structural features of the FLICE-inhibitory protein (c-FLIP) isoforms. Each of the three c-FLIP isoforms, c-FLIPL, c-FLIPS, and c-FLIPR, contain two tandem death effector domains (DEDs) at its N-terminus. c-FLIPL, the long c-FLIP isoform, is similar in overall structure to procaspase-8, but its caspase-like domain is functionally inactive. Other than the two DEDs, the short c-FLIP isoforms c-FLIPS and c-FLIPR only include a short C-terminus.