2'-5'-oligoadenylate synthase (IPR026774)

Short name: 2-5A_synthase

Overlapping homologous superfamilies

Family relationships



2-5A synthases (2'-5'-oligoadenylate synthases) are interferon-induced antiviral enzymes that recognise virally produced dsRNA and initiate RNA destabilisation through activation of RNase L within infected cells [PMID: 12799444]. It synthesises higher oligomers of 2'-5'-oligoadenylates (2-5A) from ATP which then bind to the inactive monomeric form of ribonuclease L (RNase L) leading to its dimerisation and subsequent activation. The activation of RNase L leads to degradation of cellular as well as viral RNA, resulting in the inhibition of protein synthesis, thus terminating viral replication. It can mediate the antiviral effect via the classical RNase L-dependent pathway or an alternative antiviral pathway independent of RNase L [PMID: 21142819, PMID: 18931074].

It's worth noting that some proteins in this family do not have 2'-5'-oligoadenylate synthase activity, including 2-5A synthase 1B, 2'-5'-oligoadenylate synthase-like protein 1 and 2'-5'-oligoadenylate synthase-like protein. However, they can bind double-stranded RNA and display antiviral activity via an alternative antiviral pathway independent of RNase L [PMID: 20074559, PMID: 12396720, PMID: 16371364].

GO terms

Biological Process

GO:0051607 defense response to virus

Molecular Function

GO:0003725 double-stranded RNA binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.