Cysteine Toxicity Drives Age-Related Mitochondrial Decline by Altering Iron Homeostasis

Publication date: 23 January 2020Source: Cell, Volume 180, Issue 2Author(s): Casey E. Hughes, Troy K. Coody, Mi-Young Jeong, Jordan A. Berg, Dennis R. Winge, Adam L. HughesSummaryMitochondria and lysosomes are functionally linked, and their interdependent decline is a hallmark of aging and disease. Despite the long-standing connection between these organelles, the function(s) of lysosomes required to sustain mitochondrial health remains unclear. Here, working in yeast, we show that the lysosome-like vacuole maintains mitochondrial respiration by spatially compartmentalizing amino acids. Defects in vacuole function result in a breakdown in intracellular amino acid homeostasis, which drives age-related mitochondrial decline. Among amino acids, we find that cysteine is most toxic for mitochondria and show that elevated non-vacuolar cysteine impairs mitochondrial respiration by limiting intracellular iron availability through an oxidant-based mechanism. Cysteine depletion or iron supplementation restores mitochondrial health in vacuole-impaired cells and prevents mitochondrial decline during aging. These results demonstrate that cysteine toxicity is a major driver of age-related mitochondrial deterioration and identify vacuolar amino acid compartmentation as a cellular strategy to minimize amino acid toxicity.Graphical Abstract

Source: Cell - January 25, 2020 Category: Cytology Source Type: research