Deconjugating enzymes (DCEs) are proteases that process ubiquitin or ubiquitin-like gene products, reverse the modification of proteins by a single ubiquitin or ubiquitin-like protein (UBL) and remodel polyubiquitin (or poly-UBL) chains on target proteins (Reyes-Turcu et al., 2009). The deubiquitylating - or deubiquitinating - enzymes (DUBs) represent the largest family of DCEs and regulate ubiquitin dependent signalling pathways. The activities of the DUBs include the generation of free ubiquitin from precursor molecules, the recycling of ubiquitin following substrate degradation to maintain cellular ubiquitin homeostasis and the removal of ubiquitin or ubiquitin-like proteins (UBL) modifications through chain editing to rescue proteins from proteasomal degradation or to influence cell signalling events (Komander et al., 2009). There are two main classes of DUB, cysteine proteases and metalloproteases. Ubiquitin specific protease 27X (USP27X) is a member of the cysteine protease enzyme family and cloning of the gene was first described by Puente et al. (2003). Although closely related to USP22, which deubiquitylates histones, USP27X lacks the N-terminal ubiquitin binding protein zinc finger domain, suggesting it does not have the ability to deubiquitylate histones (Puente et al., 2003).
Komander D, Clague MJ and Urbe S (2009) Breaking the chains: structure and function of the deubiquitinases. Nat Rev Mol Cell Biol 10, 550-563.
Lee DW, Peggie M, Deak M, Toth R, Gage ZO, Wood N, et al. (2012) The Dac-tag, an affinity tag based on penicillin-binding protein 5. Anal Biochem 428, 64-72.
Puente XS, Sanchez LM, Overall CM and Lopez-Otin C (2003) Human and mouse proteases: a comparative genomic approach. Nature reviews. Genetics 4, 544-558.
Reyes-Turcu FE, Ventii KH and Wilkinson KD (2009) Regulation and cellular roles of ubiquitin-specific deubiquitinating enzymes. Ann Rev Biochem 78, 363-397.