Ubiquitin carboxyl-terminal hydrolase 4 (USP4) is a specialized cysteine protease with a predicted molecular weight of 109 kDa. USP4 is a member of the peptidase C19 family and the human protein shares 91% amino acid sequence identity with its mouse ortholog. USP4 is ubiquitinated on multiple sites, and deubiquitination of these sites requires USP4 catalytic activity. USP4 interacts with CtIP protein and the MRN (MRE11-RAD50-NBS1) complex to promote DNA double-strand break repair. Other reported USP4 targets include HDAC2, ADORA2A, PDPK1 and TRIM21.
Use & Storage
Reaction conditions will need to be optimized for each specific application. We recommend an initial USP4 concentration of 10-100 nM when using Ubiquitin-AMC or Ubiquitin-Rh110 substrates (U-550, U-555)