Calcium-regulated non-lysosomal thiol-protease which catalyzes limited proteolysis of substrates involved in cytoskeletal remodeling and signal transduction. Heterodimer of a large (catalytic) and a small (regulatory) subunit. Expressed exclusively in testis, where it is restricted to spermatocytes and during the later stages of meiosis (at protein level). Belongs to the peptidase C2 family.