Component of the spermatoproteasome, a proteasome specifically found in testis that promotes acetylation-dependent degradation of histones, thereby participating actively to the exchange of histones during spermatogenesis. The proteasome is a protein complex that degrades unneeded or damaged proteins by proteolysis, a chemical reaction that breaks peptide bonds. Required for 20S core proteasome assembly, essential for the degradation of meiotic proteins RAD51 and RPA1 at late prophase I and the progression of meiosis I during spermatogenesis. Localizes to the synaptonemal complex, a 'zipper'-like structure that holds homologous chromosome pairs in synapsis during meiotic prophase I.