The switch between mitochondrial respiration and fermentation as the main ATP production pathway through an increase glycolytic flux is known as the Crabtree effect. The elucidation of the molecular mechanism of the Crabtree effect may have important applications in ethanol production and lay the groundwork for the Warburg effect, which is essential in the molecular etiology of cancer. A key piece in this mechanism could be Snf1p, which is a protein that participates in the nutritional response including glucose metabolism. Thus, this work aimed to recognize the role of the SNF1 gene on the glycolytic flux and mitochondrial respiration through the glucose concentration variation to gain insights about its relationship with the Crabtree effect. Herein, we found that SNF1 deletion in Saccharomyces cerevisiae cells grown at 1% glucose, decreased glycolytic flux, increased NAD(P)H concentration, enhanced HXK2 gene transcription, and decreased mitochondrial respiration. Meanwhile, the same deletion increased the mitochondrial respiration of cells grown at 10% glucose. Altogether, these findings indicate that SNF1 is important to respond to glucose concentration variation and is involved in the switch between mitochondrial respiration and fermentation.

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The switch of mitochondrial respiration to fermentation as the main pathway to produce ATP through the increase of glycolytic flux is known as the Crabtree effect. The elucidation of the molecular mechanism of the Crabtree effect may have important applications in ethanol production and lay the groundwork for the Warburg effect, which is essential in the molecular etiology of cancer. A key piece in this mechanism could be Snf1p, which is a protein that participates in the nutritional response that includes glucose metabolism. Thus, this work aimed to recognize the role of the SNF1 complex on the glycolytic flux and mitochondrial respiration, to gain insights about its relationship with the Crabtree effect. Herein, we found that in Saccharomyces cerevisiae cells grown at 1% glucose, mutation of SNF1 gene decreased glycolytic flux, increased NAD(P)H, enhanced HXK2 gene transcription, and decreased mitochondrial respiration. Meanwhile, the same mutation increased the mitochondrial respiration of cells grown at 10% glucose. Moreover, SNF4 gene deletion increased respiration and growth at 1% of glucose. In the case of the GAL83 gene, we did not detect any change in mitochondrial respiration or growth. Altogether, these findings indicate that SNF1 is vital to switch from mitochondrial respiration to fermentation.