2′-5′-oligoadenylate synthetase 1 (OAS1) is an interferon-inducible double-stranded RNA (dsRNA) sensor, which is expressed as multiple isoforms generated by alternative splicing (Bonnevie-Nielsen V et al., 2005; Li H et al., 2017; Di H et al., 2020; Soveg FW et al., 2021). The OAS1 p46 isoform, OAS1(1-400), contains a C-terminal CaaX motif (CTIL) that undergoes post-translational geranylgeranylation (Soveg FW et al., 2021; Wickenhagen A et al., 2021). This lipidation modification targets OAS1 p46 to the cytosolic face of intracellular membranes, enhancing its ability to detect membrane-protected viral double-stranded RNA (dsRNA) intermediates in the viral replication sites (Soveg FW et al., 2021; Wickenhagen et al, 2021). Upon binding to viral dsRNA, OAS1 p46 undergoes a conformational change that reveals its catalytic pocket, enabling synthesis of the second messenger 2′-5′-linked oligoadenylates (2′-5′A) from ATP in the presence of Mg²⁺ ions (Donovan J et al., 2013). The 2′-5′A produced by OAS1 p46 binds to the latent endoribonuclease RNase L, leading to its activation (Donovan J et al., 2013; 2017). Activated RNase L cleaves both cellular and viral RNA, resulting in inhibition of viral replication.