OAS antiviral response

The human oligoadenylate synthetase (OAS) family consists of four proteins whose production is stimulated by interferon, OAS1, OAS2, OAS3, and OASL. The first three members have the 2'-5'-oligoadenylate synthetase activity for which the family is named (Sadler AJ & Williams BR 2008), whereas OASL is devoid of this activity despite sharing significant sequence similarity with the other OAS proteins (Zhu J et al. 2015). OAS1, 2, and 3 are activated by double-stranded RNA to synthesize 5'-triphosphorylated 2'-5'-oligoadenylates (2-5A) from ATP (Kerr IM & Brown RE 1978). The 2-5A serve as chemically unique second messengers that induce regulated RNA decay by activating ribonuclease L (RNase L), thus mediating antiviral innate immunity (Zhou A et al. 1993; Lin RJ et al. 2009; Huang H et al. 2014; Han Y et al. 2014). RNase L has also been implicated in antibacterial innate immunity (Li XL et al. 2008). RNase L cleaves single-stranded RNA (ssRNA) in U-rich sequences, typically after UU or UA dinucleotides leaving a 5'-OH and 2',3'-cyclic phosphate (Floyd-Smith G et al. 1981; Wreschner DH et al.1981; Cooper DA et al. 2014).

Summary from Reactome (R-HSA-8983711), read 2026-09-23.