Cover image

Innate immune receptor for RNA (PDB id: 8DVU; Wang W, Pyle AM. 2022. The RIG-I receptor adopts two different conformations for distinguishing host from viral RNA ligands. Mol Cell 82: 4131–4144.e6). RIG-I, an innate immune receptor for RNA, specifically recognizes the unique molecular features of viral RNA molecules and selectively distinguishes them from closely related RNAs abundant in host cells. Upon binding viral RNA, RIG-I adopts a high-affinity conformation that is conducive to signaling, while host RNA induces an autoinhibited conformation that stimulates RNA release. RNA is displayed in NDB colors: A—red, C—yellow, G—green, U—cyan; ADP, Mg2+ (lime), and Zn2+ (purple) ligands are shown in spacefill. RIG-I protein (residues 240-922) is displayed as a wheat-colored ribbon. A 13-residue unmodeled segment is indicated by dashed line. Cover image provided by the Nucleic Acid Knowledgebase (nakb.org). Image generated using ChimeraX (Protein Sci 30: 70–82).