Sperm surface membrane protein that may be involved in spermatogenesis and fertilization. This is a non catalytic metalloprotease-like protein (By similarity). Expressed specifically in testis. A tripeptide motif (ECD) within disintegrin-like domain could be involved in the binding to egg integrin receptor and thus could mediate sperm/egg binding. The prodomain and the metalloprotease-like domain are cleaved during the epididymal maturation of the spermatozoa.