The IFIT2-IFIT3 antiviral complex targets short 5' untranslated regions on viral mRNAs for translation inhibition.

ABSTRACT: Recognition of foreign RNA is critical for the innate immune response to viruses. Interferon (IFN)-induced proteins with tetratricopeptide repeats (IFIT) 2 and 3 are highly upregulated following viral infection, but mechanistic insight into their antiviral role is lacking. Here we demonstrate that short 5' untranslated regions (UTRs), a characteristic of many viral mRNAs, can serve as a molecular pattern for innate immune recognition via IFIT2 and IFIT3. Structure determination of the IFIT2-IFIT3 complex at 3.2 Å using cryo-EM reveals a domain-swapped heterodimer that is required for recognition of the viral mRNA 5' end, translation inhibition and antiviral activity. Critically, viral or host 5' UTR lengths less than 50 nucleotides are necessary and sufficient to enable translation inhibit

SUBMITTER: Glasner DR 

PROVIDER: S-EPMC12570964 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature