interferon-stimulated gene 20 kD protein; estrogen-regulated transcript 45 protein; promyelocytic leukemia nuclear body-associated protein ISG20 (ISG20, HEM45)

Function: 1) exonuclease with specificity for single-stranded RNA 2) lesser activity towards DNA (35-fold) 3) involved in antiviral function of IFN against RNA viruses 4) exonucleolytic cleavage in the 3'- to 5'- direction 5) yields nucleoside 5'-phosphates 6) component of PML NB complex - associates with PML & SP100 in the PML NB complex Cofactor: Mn+2 Kinetic parameters: - Optimum pH is 7.0 Structure: belongs to the exonuclease superfamily Compartment: nucleus Alternative splicing: named isoforms=2 Expression: - expressed in peripheral blood leukocytes, spleen, thymus, colon, lung - induced by interferon-alpha & interferon-beta - weaker induction by interferon-gamma Pathology: - stable & constitutive expression confers resistance* to a) vesicular stomatitis virus (VSV) b) influenza virus c) encephalomyocarditis virus (EMCV) * resistance to infection in HeLa cells - up regulated by E2 in estrogen receptor-positive breast cancer cell lines

General

exoribonuclease nuclear protein

Properties

SIZE: entity length = 181 aa MW = 20 kD COMPARTMENT: cell nucleus MOTIF: active site

Database Correlations

OMIM 604533 UniProt Q96AZ6 Pfam PF00929 Entrez Gene 3669 Kegg hsa:3669 ENZYME 3.1.13.1

References

UniProt :accession Q96AZ6