Yeast as a Tool to Study Signaling Pathways in Mitochondrial Stress Response and Cytoprotection

Figure 1

AA-PCD pathways. Acetic acid enters in yeast cells and dissociates into acetate and protons causing intracellular acidification. H₂O₂ accumulates, SOD activity increases, while catalase activity is undetectable. En route to AA-PCD, cyt c is released and works as an electron donor (c_red) to mitochondrial respiratory chain and as superoxide anion (O_2−•) scavenger (c_ox). In a late phase, cyt c is degraded by unidentified proteases. Mitochondrial functions progressively decline with decrease in mitochondrial membrane potential (ΔΨ), respiratory control index (RCI) and COX activity. Caspase-like activity increases in a late phase (red lines). Alternative programmed cell death is induced by acetic acid in YCA1 and/or cyt c knockout cells or in mutant cyt c cells (blue lines).