• Purity

  >98%, by SDS-PAGE under reducing conditions and visualized by Colloidal Coomassie® Blue stain.

• Activity

  Reaction conditions will need to be optimized for each specific application.  We recommend an initial recombinant murine USP18 concentration of 100-250 nM when using ISG15-AMC (    UL-553) as a substrate.

• Source

  Spodoptera frugiperda,     Sf 21 (baculovirus)-derived Contains an N-terminal 6-His tag, Ser47 - Ser368

• Accession #

• Predicted Molecular Mass

  38 kDa

Background: USP18

Ubiquitin-like carboxyl-terminal hydrolase 18 (USP18) is a specialized cysteine protease with a predicted molecular weight of 42 kDa.  USP18 from   Mus musculus is a member of the peptidase C19 family and shares 70% amino acid identity with its human ortholog.  USP18 plays and important role in antiviral responses and interferon-mediated signaling pathways.  Mice lacking the gene (USP18  ^-/-) are hypersensitive to interferon, have shortened lifespans and pathologic abnormalaties of the brain.  While it was initially speculated that the cause of these phenotypes stems from the accumulaiton of ISG15-conjugated intracellular proteins (a target for USP18 catalytic function), it was later demonstrated that USP18 has multiple roles, at least one of which is independent of its ISGylase activity.

• References:

1. Goldmann, T. et al. (2015) EMBO J.  34: 1612

2. Ketscher, L. & Knobeloch, K.P. (2015) Cytokine  76: 569

3. Knobeloch, K.P. et al. (2005) Mol. Cell Biol.  25: 11030

4. Speer, S.D. et al. (2016) Nat. Commun.  doi: 10.1038/ncomms11496

• Long Name:

  Ubiquitin Specific Peptidase 18

• Entrez Gene IDs:

  11274 (Human); 24110 (Mouse); 312688 (Rat)

• Alternate Names:

  EC 3.1.2.15; EC 3.4.19.-; hUBP43; ISG15-specific-processing protease; ISG43; ISG43UBP43; ubiquitin specific peptidase 18; ubiquitin specific protease 18; ubl carboxyl-terminal hydrolase 18; ubl thioesterase 18,43 kDa ISG15-specific protease; Ubl thiolesterase 18; UBP43; USP18