The emerging role of the interferon-induced PKR protein kinase as an apoptotic effector: A new face of death?

Recent research has thrown a spotlight on the interferon (IFN)-induced PKR protein kinase, implicating it as an important effector of apoptosis induce d by several cellular stress conditions, including viral infection, cytokin e treatment, and growth factor deprivation. In this review, we summarize th e evidence for the role of PKR as a death accomplice and discuss how PKR mi ght promote cell demise in light of current knowledge of the molecular mech anisms of apoptosis. Given its new found role and its established antiviral function, it is no wonder that PKR is a popular target for viral evasion o f the host defense. PKR-dependent apoptosis may offer a novel cell-death pa thway for specific manipulation in therapeutic strategies against apoptosis -related diseases.