Ubiquitin modifications can be reversed by the reaction of enzymes collectively known as deubiquitinating enzymes (DUBs). Deubiquitination is performed by the action of DUBs, ubiquitin specific proteases that can reverse target-protein ubiquitination by editing or disassembling polyubiquitin chains. DUBs play an important role in several aspects of the ubiquitin-proteasome system, and mutations in genes expressing DUBs have been implicated in a number of diseases, including hereditary cancer and neurodegeneration.