Enables chromatin binding activity. Involved in histone H2B conserved C-terminal lysine deubiquitination; regulation of transcription by RNA polymerase II; and stem cell differentiation. Acts upstream of or within neuron fate commitment. Part of ESC/E(Z) complex and elongin complex. Orthologous to human EPOP (elongin BC and polycomb repressive complex 2 associated protein). [provided by Alliance of Genome Resources, Apr 2022]