A Short Peptide at the Amino Terminus of the Sendai Virus C Protein Acts as an Independent Element That Induces STAT1 Instability

摘要: The Sendai virus C protein acts to dismantle the interferon-induced cellular antiviral state in an MG132-sensitive manner, part by inducing STAT1 instability. This activity of maps first 23 amino acids (C(1-23)) 204-amino-acid (aa)-long (C(1-204)). C(1-23) was found act as independent viral element that induces instability, since this peptide fused green fluorescent (C(1-23)/GFP) is at least active C(1-204) respect. also degradation C(1-23)/GFP and other proteins which it fused. Most C(1-204), particularly its amino-terminal half, predicted be structurally disordered. a disordered circular dichroism, 11 aa have strong potential form amphipathic alpha-helix low concentrations trifluoroethanol, thought mimic protein-protein interaction. critical degradation-determining sequence mapped mutation eight residues near N terminus: (4)FLKKILKL(11). All large hydrophobic (4)FLKKILKL(11), plus ability alpha-helix, were for degradation. In contrast, self-degradation did not require (8)ILKL(11), nor throughout region. Remarkably, stimulated degradation, trans required same determinants STAT1. Our results suggest coordinates dual activities regulating RNA synthesis counteracting host innate response sensing both own intracellular concentration