This gene encodes a cell-surface anchored serine protease, which is a member of the trypsin family of serine proteases. The encoded protein is predicted to be active on peptide linkages involving the carboxyl group of lysine or arginine. The encoded protein localizes to the cytoplasm and the plasma membrane of premeiotic testicular germ cells and may be involved in progression of testicular tumors of germ cell origin. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene.,PRSS21,ESP-1,ESP1,TEST1,TESTISIN,testisin,Cancer,Signal Transduction,Kinase,Serine/threonine kinases,Cell Biology & Developmental Biology,Ubiquitin,PRSS21