Coated vesicles are implicated in a number of receptor-mediated transport events within eukaryotic cells. In particular, they are required for the export of newly synthesized lysosomal enzymes from the trans-Golgi network, and at the plasma membrane they are responsible for receptor-mediated endocytosis of selected ligands (1 ). Coated vesicles are the best characterized of all transport organelles, owing in large measure to the ease with which they can be purified.
