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

Figure 2

Signaling pathways possibly involved in the interplay between cell death and cytoprotection processes in yeast cells in response to acetic acid stress. Acetic acid causes intracellular acidification, mitochondrial dysfunction, and cell death. TOR pathway is involved in the signaling of AA-PCD; rapamycin inhibition of TOR can trigger autophagy and RTG target gene expression. Dotted lines indicate the hypothetical signaling pathways in AA-PCD regulation in response to mitochondrial dysfunction, on the basis of indirect experimental evidence (see text for details). Intracellular acidification stimulates RAS-cAMP signaling pathway, causing mitochondrial dysfunction, which may lead to AA-PCD or activate retrograde response inducing AA-PCD resistance. RAS pathway negatively regulates Mks1p, a negative regulator of RTG pathway. Positive and negative regulators of RTG pathway are shown in blue and red, respectively. TOR signaling is found at the crossroad of RTG, AA-PCD, and autophagy pathways.