Download MendeleyThe C-Terminal Regulatory Domain Is the RNA 5'-Triphosphate Sensor of RIG-I.
Cui, S., Eisenacher, K., Kirchhofer, A., Brzozka, K., Lammens, A., Lammens, K., Fujita, T., Conzelmann, K.K., Krug, A., Hopfner, K.P.(2008) Mol Cell 29: 169-179
- PubMed: 18243112
- DOI: https://doi.org/10.1016/j.molcel.2007.10.032
- Primary Citation of Related Structures:
2QFB, 2QFD - PubMed Abstract:
The ATPase RIG-I senses viral RNAs that contain 5'-triphosphates in the cytoplasm. It initiates a signaling cascade that activates innate immune response by interferon and cytokine production, providing essential antiviral protection for the host. The mode of RNA 5'-triphosphate sensing by RIG-I remains elusive. We show that the C-terminal regulatory domain RD of RIG-I binds viral RNA in a 5'-triphosphate-dependent manner and activates the RIG-I ATPase by RNA-dependent dimerization. The crystal structure of RD reveals a zinc-binding domain that is structurally related to GDP/GTP exchange factors of Rab-like GTPases. The zinc coordination site is essential for RIG-I signaling and is also conserved in MDA5 and LGP2, suggesting related RD domains in all three enzymes. Structure-guided mutagenesis identifies a positively charged groove as likely 5'-triphosphate-binding site of RIG-I. This groove is distinct in MDA5 and LGP2, raising the possibility that RD confers ligand specificity.
Organizational Affiliation:
Gene Center, Department of Chemistry and Biochemistry, Ludwig-Maximilians-University of Munich, Feodor-Lynen-Strasse 25, 81377 Munich, Germany.
