title: Conformational rearrangements of RIG-I receptor on formation of a multiprotein:dsRNA assembly.
abstract: The retinoic acid inducible gene-I (RIG-I)-like family of receptors is positioned at the front line of our innate cellular defence system. RIG-I detects and binds to foreign duplex RNA in the cytoplasm of both immune and non-immune cells, and initiates the induction of type I interferons and pro-inflammatory cytokines. The mechanism of RIG-I activation by double-stranded RNA (dsRNA) involves a molecular rearrangement proposed to expose the N-terminal pair of caspase activation recruitment domains, enabling an interaction with interferon-beta promoter stimulator 1 (IPS-1) and thereby initiating downstream signalling. dsRNA is particularly stimulatory when longer than 20 bp, potentially through allowing binding of more than one RIG-I molecule. Here, we characterize full-length RIG-I and RIG-I subdomains combined with a stimulatory 29mer dsRNA using multi-angle light scattering and size-exclusion chromatography-coupled small-angle X-ray scattering, to build up a molecular model of RIG-I before and after the formation of a 2:1 protein:dsRNA assembly. We report the small-angle X-ray scattering-derived solution structure of the human apo-RIG-I and observe that on binding of RIG-I to dsRNA in a 2:1 ratio, the complex becomes highly extended and flexible. Hence, here we present the first model of the fully activated oligomeric RIG-I.
authors: Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia.
authors: Simone A
authors: SA
authors: Beckham
authors: Jason
authors: J
authors: Brouwer
authors: Anna
authors: A
authors: Roth
authors: Die
authors: D
authors: Wang
authors: Anthony J
authors: AJ
authors: Sadler
authors: Matthias
authors: M
authors: John
authors: Kerstin
authors: K
authors: Jahn-Hofmann
authors: Bryan R G
authors: BR
authors: Williams
authors: Jacqueline A
authors: JA
authors: Wilce
authors: Matthew C J
authors: MC
authors: Wilce
mesh_terms: D001059:Apoproteins / Q000737:chemistry*; D002850:Chromatography, Gel; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D012330:RNA, Double-Stranded / Q000737:chemistry*; D011971:Receptors, Immunologic; D053838:Scattering, Small Angle; D014357:Trypsin / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D001059:Apoproteins; D010446:Peptide Fragments; D012330:RNA, Double-Stranded; D011971:Receptors, Immunologic; D014357:Trypsin; C452820:RIGI protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases