FLIP Proteins and Enzymes

FLIP (Flice-like Inhibitory Protein), also known as I-FLICE, CASPER, and FLAME-1, is an apoptosis inhibitory protein with architecture similar to that of Caspases-8 and -10. Both of the FLIP isoforms, Long (L) and Short (S), contain two death effector domains (DED). FLIP(L) has a C-terminal Caspase-like protease domain which lacks both a catalytic active site and residues that form a substrate-binding pocket. FLIP(S) and FLIP(L) interact with the adaptor molecule FADD, and potently inhibit apoptosis initiated by Fas Ligand/TNF signaling pathways.