The structural basis of 5' triphosphate double-stranded RNA recognition by RIG-I C-terminal domain.
RIG-I is a cytosolic sensor of viral RNA that plays crucial roles in the induction of type I interferons. The C-terminal domain (CTD) of RIG-I is responsible for the recognition of viral RNA with 5' triphosphate (ppp). However, the mechanism of viral RNA recognition by RIG-I is still not fully understood. Here, we show that RIG-I CTD binds 5' ppp dsRNA or ssRNA, as well as blunt-ended dsRNA, and exhibits the highest affinity for 5' ppp dsRNA. Crystal structures of RIG-I CTD bound to 5' ppp dsRNA with GC- and AU-rich sequences revealed that RIG-I recognizes the termini of the dsRNA and interacts with the 5' ppp through extensive electrostatic interactions. Mutagenesis and RNA-binding studies demonstrated that similar binding surfaces are involved in the recognition of different forms of RNA. Mutations of key residues at the RNA-binding surface affected RIG-I signaling in cells.
Lu
Cheng
C
Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
Xu
Hengyu
H
Ranjith-Kumar
C T
CT
Brooks
Monica T
MT
Hou
Tim Y
TY
Hu
Fuqu
F
Herr
Andrew B
AB
Strong
Roland K
RK
Kao
C Cheng
CC
Li
Pingwei
P
D001483:Base Sequence; D002850:Chromatography, Gel; D018360:Crystallography, X-Ray; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D004926:Escherichia coli; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011122:Polyphosphates / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D012330:RNA, Double-Stranded / Q000737:chemistry / Q000378:metabolism*; D011971:Receptors, Immunologic; D017422:Sequence Analysis, DNA; D020349:Surface Plasmon Resonance; D014461:Ultracentrifugation
D011122:Polyphosphates; D012330:RNA, Double-Stranded; D011971:Receptors, Immunologic; C452820:RIGI protein, human; D000071457:DEAD Box Protein 58; D053487:DEAD-box RNA Helicases; C005692:triphosphoric acid