Deubiquitinating enzyme that cleaves both 'Lys-48'-linked and 'Lys-63'-linked poly-ubiquitin chains (in vitro) (PubMed:21118805). Acts as a deubiquitinating enzyme for the transcription factor KLF5, playing a role in the regulation of KLF5 stability (PubMed:26079537). . This is the function of Ensembl gene identifier ENSG00000123594 (ATXN3L, ataxin 3 like).