Zinc homeostasis in the secretory pathway in yeast.

It is estimated that up to 10% of proteins in eukaryotes require zinc for their function. Although the majority of these proteins are located in the nucleus and cytosol, a small subset is secreted from cells or is located within an intracellular compartment. As many of these compartmentalized metalloproteins fold to their native state and bind their zinc cofactor inside an organelle, cells require mechanisms to maintain supply of zinc to these compartments even under conditions of zinc deficiency. At the same time, intracellular compartments can also be the site for storing zinc ions, which then can be mobilized when needed. In this review, we highlight insight that has been obtained from yeast models about how zinc homeostasis is maintained in the secretory pathway and vacuole.