Description
The Saposin family includes four structurally related proteins, saposin A, B, C, and D which are ~80 aa small acidic acitvator proteins with specificities for glycosphingolipid (GSL) hydrolases. They are derived from a single precursor, prosaposin. In both humans and mice, prosaposin/saposin deficiencies lead to severe neurological deficits. Saposins are processed from prosaposin in the late endosome and lysosome, and their stability is maintained by three disulfide bridges. The post-modified prosoposin is an ~70 kDa form which subsequently undergoes partial proteolysis to produce saposin A, B, C, and D, each proteins are between 12-14 kDa in mass