Interferon-induced 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. Single-stranded PPP-RNAs, which lack 2'-O-methylation of the 5' cap and bear a 5'-triphosphate group instead, are specific 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 manner. Also recognizes and binds tRNAs.Rogers J., Nature 429:375-381(2004).Venter J.C., Submitted (SEP-2005).Bennett K.L., Submitted (OCT-2008).