Molecular role of sulfated glycoprotein-1 (SGP-1/prosaposin) in Sertoli cells.

Sulfated Glycoprotein-1 (SGP-1) is a major polypeptide secreted by rat Sertoli cells. Sequence analysis revealed a 70% sequence similarity with human prosaposin and a 80% similarity with mouse prosaposin. Both human and mouse prosaposin are 65-70 kDa proteins cleaved in the lysosomes into four 10-15 kDa proteins designated saposins A, B, C and D. Lysosomal saposins function as enzymatic activators that promote the hydrolysis of certain …