The Structures and Functions of Vaccinia Virus E3L and Protein Kinase R |Biomedgrid

The Vaccinia Virus (VV) E3L of the poxvirus family encodes double-stranded RNA-binding, which promote viral growth and pathogenesis by inhibiting innate immunity. E3L gene of vaccinia virus also acts as a multifunctional viral immune factor that blocks host defense factors from participating in the induction and action of Interferon (IFN). In other words, the main function of E3L is to block the activations of Interferon Regulatory Factor 3 (IRF3), RNase L, and Protein Kinase R (PKR) simultaneously. These inhibitions may be achieved by combining Double-Stranded RNA (dsRNA) isolation with direct inhibitions of protein-protein interactions. Meanwhile, dsRNA-dependent serine/threonine protein kinase induced by IFN plays a key role in innate immune response to viral infection and key regulatory roles during signal transduction, cell proliferation and differentiation, and apoptosis. Furthermore, activation of PKR inhibits protein translation by Eukaryotic Translation Initiation Factor 2-Alpha Kinase 2 (EIF2AK2) at peak viral infection. In this review manuscript we focus on the activity of the vaccinia virus E3L protein and in the PKR host protein, describing their functions and interactions to provide new ideas regarding for vaccine development and the developments of antiviral drugs.