The short form of cellular FLIP (FLIP(S) or c-FLIPS) has two death effector domains DEDs, which can bind to FADD and caspase-8 (CASP8). FLIP(S) protects the cells from apoptosis by inhibiting the processing of caspase-8 at the receptor level (Scaffidi C et al. 1999; Micheau O et al 2001).
FLIP(S) is a short-lived protein which is sensitive to ubiquitination and proteasomal degradation (Poukkula M et al. 2005). Protein kinase C (PKC)- mediated phosphorylation of FLIP(S) at Ser193 was shown to prolongs the half-life of FLIP(S) by inhibiting its polyubiquitination (Kaunisto A et al. 2009).