Cd2+ and Zn2+ induce autophagy in the Saccharomyces cerevisiae.

It is generally considered that autophagy can selectively remove or isolate the damaged macromolecules & organelles, & even facilitate cells death. Such mechanism is to avoid these particles or cells disturbing normal cellular functions and physiology. The purposes of this study are to test the conditions that excess cadmium (Cd2+) & Zinc (Zn2+) induce autophagy. Based on the experimental data, we found that cadmium & zinc inhibit the growth of yeasts at 10μM & 5mM, respectively. Excess heavy metal actually induced autophagic protein expression & caused autophagosomes accumulated in the vacuole of protein-deficient yeast cells. Our results show that there are close connections between heavy metal toxicity and autophagy induction in the yeast. With further characterization of the molecular mechanisms of the autophagy & the cytoplasm to vacuole targeting pathways, it may help us to understand & handle the issues of heavy metal toxicity in higher organisms.