Intracellular traffic of the mannose 6-phosphate receptor and its ligands

The role of the mannose 6-phosphate recognition marker and the phosphomannosyl receptor in the intracellular transport of acid hydrolases is well established. Several details of the process, however, are presently unclear and warrant further investigation (Table 1). The development of in vitro systems for the reconstitution of receptor-mediated endocytosis and intracellular transport, together with the application of the techniques of molecular biology to this field, should lead to major advances in our understanding of the targeting of enzymes to lysosomes.