Zinc deficiency: An unexpected trigger for autophagy

Cells respond to deprivation of certain nutrients such as glucose or nitrogen by inducing autophagy, reclaiming pieces of proteins for use in critical functions. A recent study shows that, in yeast, zinc depletion acts in a similar fashion. Depletion of this essential nutrient induces non-selective autophagy by inhibiting TORC1, leading to release and recycling of zinc from degraded proteins. Cells respond to deprivation of certain nutrients such as glucose or nitrogen by inducing autophagy, reclaiming pieces of proteins for use in critical functions. A recent study shows that, in yeast, zinc depletion acts in a similar fashion. Depletion of this essential nutrient induces non-selective autophagy by inhibiting TORC1, leading to release and recycling of zinc from degraded proteins. Zinc starvation induces autophagy in yeastJournal of Biological ChemistryVol. 292Issue 20PreviewZinc is an essential nutrient for all forms of life. Within cells, most zinc is bound to protein. Because zinc serves as a catalytic or structural cofactor for many proteins, cells must maintain zinc homeostasis under severely zinc-deficient conditions. In yeast, the transcription factor Zap1 controls the expression of genes required for uptake and mobilization of zinc, but to date the fate of existing zinc-binding proteins under zinc starvation remains poorly understood. Autophagy is an evolutionarily conserved cellular degradation/recycling process in which cytoplasmic proteins and organelles are sequestered for degradation in the vacuole/lysosome.