Predicted to enable endopeptidase activity. Involved in fat cell differentiation. Acts upstream of or within antigen processing and presentation. Part of proteasome core complex and spermatoproteasome complex. Is expressed in thymus primordium. Human ortholog(s) of this gene implicated in JMP syndrome. Orthologous to human PSMB8 (proteasome 20S subunit beta 8). [provided by Alliance of Genome Resources, Apr 2022]