Interferon-Induced and Double-Stranded RNA-Activated Enzymes: A Specific Protein Kinase and 2′,5′-Oligoadenylate Synthetases

Abstract

Treatment of cells with interferon (IFN) results in the induction of two double-stranded RNA (dsRNA)-activated enzymes: a specific protein kinase and 2′-5′ linked oligoadenylate [pppA(2′p5′A)_n referred to as 2-5A] synthetases. The protein kinase, when activated by dsRNA, becomes autophosphorylated and catalyzes and phosphorylation of the protein synthesis initiation factor, eIF2. The 2-5A synthetases, when activated by dsRNA, form 2-5A molecules capable of activating a latent endoribonuclease that degrades RNA. By inhibiting initiation of protein synthesis or by degrading of RNA, these enzymes play key roles in two independent pathways that regulate overall protein synthesis.