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Coupling/Uncoupling Reversibility in Isolated Mitochondria from Saccharomyces cerevisiae.

ABSTRACT: The yeast Saccharomyces cerevisiae uses fermentation as the preferred pathway to obtain ATP and requires the respiratory chain to re-oxidize the NADH needed for activity of Glyceraldehyde-3-phosphate. This process is favored by uncoupling of oxidative phosphorylation (OxPhos), which is at least partially controlled by the mitochondrial unspecific pore (_ScMUC). When mitochondrial ATP synthesis is needed as in the diauxic phase or during mating, a large rise in Ca²⁺ concentration ([Ca²⁺]) closes _ScMUC, coupling OxPhos. In addition, _ScMUC opening/closing is mediated by the ATP/ADP ratio, which indicates cellular energy needs. Here, opening and closing of _ScMUC was evaluated in isolated mitochondria from S. cerevisiae at different incubation times and in the presence of different ATP/ADP ratios or varying [Ca²⁺]. Measurements of the rate of O₂ consumption, mitochondrial swelling, transmembrane potential and ROS generation were conducted. It was observed that _ScMUC opening was reversible, a high ATP/ADP ratio promoted opening and [Ca²⁺] closed _ScMUC even after several minutes of incubation in the open state. In the absence of ATP synthesis, closure of _ScMUC resulted in an increase in ROS.

SUBMITTER: Morales-Garcia L

PROVIDER: S-EPMC8707985 | biostudies-literature |

REPOSITORIES: biostudies-literature

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