IFN-induced antiviral protein which inhibits expression of viral messenger RNAs lacking 2′-O-methylation of the 5′ cap. The ribose 2′-O-methylation would provide a molecular signature to distinguish between self and non-self mRNAs by the host during viral infection. Viruses evolved several ways to evade this restriction system such as encoding their own 2′-O-methylase for their mRNAs or by stealing host cap containing the 2′-O-methylation (cap snatching mechanism). Binds AU-rich viral RNAs, with or without 5′ triphosphorylation, RNA-binding is required for antiviral activity. Can promote apoptosis.
