FLIP (FLICE-like inhibitory protein) is an apoptosis regulator protein which functions as a crucial link between cell survival and cell death pathways in mammalian cells. FLIP is expressed as both long and short isoforms. The short isoform contains two death effector domains homologous to the death effector domain of the FAS-associating protein FADD. The long form contains an additional caspase-like domain, but lacks a catalytic active site and the residues that form the CLARP, Casper, I-FLICE, FLAME-1 and MRIT. This antibody binds to both isoforms.