Ubl carboxyl-terminal hydrolase 18

Involved in the negative regulation of the inflammatory response triggered by type I interferon. Upon recruitment by STAT2 to the type I IFN receptor subunit IFNAR2 interferes with the assembly of the ternary interferon-IFNAR1-IFNAR2 complex and acts as a negative regulator of the type I IFN signaling pathway. Also regulates protein ISGylation. Can efficiently cleave only ISG15 fusions including native ISG15 conjugates linked via isopeptide bonds. Necessary to maintain a critical cellular balance of ISG15-conjugated proteins in both healthy and stressed organisms.; [Isoform 2]: Has enzymatic activity similar to isoform 1 and interferes with type I interferon signaling. Major deISGylation enzyme for nuclear proteins.