Coated vesicles from rat liver and calf brain contain cryptic mannose 6-phosphate receptors

Highly purified clathrin-coated vesicles, isolated from rat liver and calf brain, contain mannose 6-phosphate receptors. The coated vesicle receptors appear to have the same subunit molecular weight and similar binding affinity as the receptor previously purified from bovine liver and rat chondrosarcoma microsomes (Sahagian, G. G., Distler, J. J., and Jourdian, G. W. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 4289-4293 and Steiner, A. W., and Rome, L. H. (1982) Arch. Biochem. Biophys. 214, 681-687). There is a considerable (greater than 60-fold) enrichment of receptors in liver coated vesicles as compared to liver microsomes. Experiments carried out with intact and detergent-disrupted coated vesicles indicated that the receptors face toward the inside of the coated vesicles. The data suggest that coated vesicles are involved in the intracellular transport of the mannose 6-phosphate receptor.