VACUOLE BIOGENESIS IN SACCHAROMYCES-CEREVISIAE - PROTEIN-TRANSPORT PATHWAYS TO THE YEAST VACUOLE

Delivery of proteins to the vacuole of the yeast Saccharomyces cerevis iae provides an excellent model system in which to study vacuole and l ysosome biogenesis and membrane traffic. This organelle receives prote ins from a number of different routes, including proteins sorted away from the secretory pathway at the Golgi apparatus and endocytic traffi c arising from the plasma membrane. Genetic analysis has revealed at l east 60 genes involved in vacuolar protein sorting, numerous component s of a novel cytoplasm-to-vacuole transport pathway, and a large numbe r of proteins required for autophagy. Cell biological and biochemical studies have provided important molecular insights into the various pr otein delivery pathways to the yeast vacuole. This review describes th e various pathways to the vacuole and illustrates how they are related to one another in the vacuolar network of S. cerevisiae.