By binding to ENY2, interferes with the nuclear functions of the deubiquitinase (DUB) module of the SAGA complex which consists of ENY2, ATXN7, ATXN7L3 and the histone deubiquitinating component USP22. Affects USP22 DUB activity toward histones indirectly by changing the subcellular distribution of ENY2 and altering ENY2 availability for ATXN7L3 interaction. Regulates H2B monoubiquitination (H2Bub1) levels through cytoplasmic sequestration of ENY2 resulting in loss of nuclear ENY2-ATXN7L3 association which destabilizes ATXN7L3. Affects protein expression levels of ENY2 and ATXN7L3. . This is the function of Ensembl gene identifier ENSG00000253719 (ATXN7L3B, ataxin 7 like 3B).