Mouse ISG15 Recombinant Protein

ISG15 (Interferon (IFN)-Stimulated Gene 15) is a ub iquitin-like protein containing two ubiquitin homology domains and becomes conjugated to a variet y of proteins when cells are treated with type I interferon or lipopolysaccharide. Therefore this mo dification (so called, ISGylation) appear to be involved in type I interferon signal transduction. Unlike ubiquitylation, ISGylation does not drive protein degradation (regulated by K48-linked ubiqui tin). ISG15 is expressed as a 165 amino acid precursor that is subsequently processed to expose the C-terminal sequence LRLRGG. Like ubiquitin, this C-terminal diglycine residue is adenlylated an d conjugated by a thiolester bond to sequential cystine residues on the E1-activating, E2-carrier a nd E3-ligase enzymes, before being transferred to lysine residues on target protein substrates. ISG15 can also be found extracellularly in an uncon jugated form. Human lymphocytes and monocytes were reported to release free ISG15 follo wing treatment with IFN- β . More than 50% of the total ISG15 could be detected in the culture me dium 24 hours following IFN stimulation. In addition, ISG15 is highly elevated and extensively conjugated to cellular proteins in many tumors and tumor cell lines. The increased levels of ISG15 in tumor cells were found to be associated with decreased levels of polyubiquitinated proteins

Full length of mouse ISG15, containing an N-termina l GST tag, expressed in E. coil. and purified by GSH agarose chromatography.

Recombinant mouse ISG15 is supplied frozen in phosp hate buffered saline (PBS) containing 10% glycerol.

42 kDa

Purity is over 90% estimated by SDS-PAGE analysis

ISG15