Analysis of autophagy activated during changes in carbon source availability in yeast cells.
Level 5 - mechanism / opinion, no new human data
Bench research in a yeast model without human participants or clinical data.
PubMed 30755486 · doi:10.1074/jbc.RA118.005698
What was done
Authors tracked autophagy induction in yeast (*Saccharomyces cerevisiae*) grown in low-glucose batch culture across three sequential metabolic states: glucose-utilizing, ethanol-utilizing, and ethanol-depleted phases. Autophagy pathways—including bulk autophagy, endoplasmic reticulum-phagy (ER-phagy), mitophagy, and microautophagy—were assessed using GFP cleavage assays via immunoblotting, fluorescence microscopy, and transmission electron microscopy. Growth rates and growth resumption were compared between wild-type and autophagy-deficient mutant yeast strains.
What was found
Bulk autophagy and ER-phagy were initiated during the ethanol-utilizing phase, with bulk autophagy further upregulated during the ethanol-depleted phase. Mitophagy was induced by ethanol depletion. Microautophagy occurred after glucose depletion and mediated the internalization of cytosolic components and lipid droplets into the vacuole. Autophagy-deficient cells displayed slower growth during the ethanol-utilizing phase and delayed growth resumption upon re-exposure to fresh medium from the ethanol-depleted phase. The abstract reports no numerical values or effect sizes.
Why it matters
This study shows that progressive carbon depletion sequentially triggers distinct selective and non-selective autophagy programs rather than a uniform stress response, clarifying cellular metabolic adaptation during nutrient transitions.
Limits
Findings are limited to a unicellular model organism (*S. cerevisiae*) and bench assays. No quantitative measurements, sample numbers, replicate counts, or effect sizes are reported in the abstract.
Cited by
- contradicts Yeast cells placed in a glucose medium shift from oxidative phosphorylation to glycolysis by destroying most of their mitochondria through mitophagy.