A stretch of 17 amino acids in the prosaposin C-terminus is critical for its binding to sortilin and targeting to lysosomes

摘要

Newly synthesized soluble lysosomal proteins are transported from the Golgi apparatus to the lysosomes by two mannose 6-phosphate receptors. However, the sphingolipid activator protein prosaposin is targeted by the alternative trafficking receptor, sortilin. Prosaposin is the precursor of four lysosomal saposins required for the hydrolysis of sphingolipids. A previous study demonstrated that the removal of its C-terminus abolished the trafficking of prosaposin to the lysosomes.