Interferon-induced protein with tetratricopeptide repeats 1 (IFIT1)

Interferon-induced antiviral RNA-binding protein that specifically binds single-stranded RNA bearing a 5'-triphosphate group (PPP-RNA), thereby acting as a sensor of viral single- stranded RNAs and inhibiting expression of viral messenger RNAs. Single-stranded PPP-RNAs, which lack two'-O-methylation of the 5' cap and keep a 5'-triphosphate group instead, are particular from viruses, providing a molecular signature to distinguish between self and non-self mRNAs by the host during viral infection.

Directly binds PPP-RNA in a non-sequence-specific method. Viruses evolved several strategies to bypass this limitation system for example encoding their own two'-O-methylase for their mRNAs or by stealing host cap containing the 2'-O-methylation (cap snatching mechanism).