TSP50 (Testis-specific protease-like protein 50) is also named as PRSS50, CT20 and belongs to the peptidase S1 family. It can enhance the expression of NFKB target genes involved in cell proliferation, and promotes cell proliferation, at least partially, through activation of the NFKB signalling pathway. There are two protein bands of 37 kDa and 43 kDa to be detected in human testes that the the difference is most likely caused by posttranslational proteolytic cleavage. The full length protein has a signal peptide with 39 amino acids and two glycosylation sites.