2'-5'-oligoadenylate synthase (OAS) (OAS)

2'-5'-Oligoadenylate synthase (OAS) is a family of interferon-induced enzymes that serve as critical sensors in the mammalian innate immune system to detect and counteract viral infections [UniProt, 2024]. Upon binding to double-stranded RNA (dsRNA) typically produced during viral replication, OAS undergoes a conformational change to catalyze the conversion of ATP into 2'-5'-linked oligoadenylates (2-5A) [PubMed, PMID: 32661141]. These 2-5A molecules function as unique second messengers that activate Ribonuclease L (RNase L), an endoribonuclease that degrades both viral and cellular single-stranded RNA to inhibit protein synthesis and viral spread [NCBI Gene, 2023]. This enzymatic pathway is essential for the antiviral effects of Type I interferons and has been strongly implicated in the host response to pathogens like SARS-CoV-2 and Hepatitis C virus [Wikipedia, 2024]. Beyond its role in infection, OAS is studied for its involvement in regulating cell proliferation and apoptosis, making it a target of interest in oncology and autoimmune research [Journal of Biological Chemistry, 2020]. Therapeutic modulation of OAS is currently achieved primarily through interferon-based therapies, though direct activation via dsRNA mimetics or small molecules remains an area of active investigation [PubChem, 2024].

Other names

2-5A synthase(2'-5')oligo(A) synthetase2'-5'-oligoadenylate synthetase 1 (OAS1)2'-5'-oligoadenylate synthetase 2 (OAS2)2'-5'-oligoadenylate synthetase 3 (OAS3)2'-5'-oligoadenylate synthetase-like protein (OASL)RNA-activated (2'-5')an synthetasep40/p46/p100

Induction of OAS gene expression via the JAK-STAT signaling pathway (by Interferons) and subsequent allosteric activation of the enzyme by viral double-stranded RNA (dsRNA). Activated OAS synthesizes 2'-5'-linked oligoadenylates (2-5A), which act as second messengers to activate Ribonuclease L (RNase L) for viral and cellular RNA degradation.