Viral and Cellular FLICE-Inhibitory Proteins: a Comparison of Their Roles in Regulating Intrinsic Immune Responses

FLICE-inhibitory proteins (FLIPs) are a family of viral (poxvirus and herpesvirus) and cellular proteins. The hallmark of this family is the presence of tandem death-effector domains (DEDs). Despite this shared motif, each protein possesses different abilities to modulate apoptosis, NF-kappa B, and interferon regulatory factor 3 (IRF3). These similarities and differences are discussed and highlighted here. The comparative study of FLIPs provides a unique basis to understand virus-host interactions, viral pathogenesis, and cellular regulation of immune system signal transduction pathways.