Impact of the Whole Genome Duplication Event on PYK Activity and Effects of a PYK1 Mutation on Metabolism in S. cerevisiae.

Hong Chen,Jamie E Blum,Zhenglong Gu,Anna Thalacker-Mercer

doi:10.3389/fmolb.2021.656461

Hong Chen, Jamie E Blum + Show 2 more

Open Access

https://doi.org/10.3389/fmolb.2021.656461

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Abstract

Background: Evolution of aerobic fermentation (crabtree effect) in yeast is associated with the whole genome duplication (WGD) event, suggesting that duplication of certain genes may have altered yeast metabolism. The pyruvate kinase (PYK) gene is associated with alterations in cell metabolism, and duplicated during the WGD, generating PYK1 and PYK2. Thus, the impact of WGD on PYK activity and role of PYK in yeast metabolism were explored.Methods: PYK activity in the presence or absence of fructose-1,6-bisphosphate (FBP) was compared between pre- and post-WGD yeast. Glucose consumption, ethanol production, and oxygen consumption were measured in wildtype yeast and yeast with a T403E point mutation, which alters FBP binding affinity.Results: FBP stimulated increased PYK activity in pre-WGD yeast and in the PYK1 isoforms of post-WGD yeast, but not in the PYK2 isoforms of post-WGD yeast. Compared to wildtype, T403E mutant yeast displayed reduced glucose consumption, reduced ethanol production, and increased mitochondrial metabolism.Conclusion: The WGD event impacted the sensitivity of PYK activity to FBP. Mutations in the FBP binding domain of PYK induce metabolic shifts that favor respiration and suppress fermentation.

Highlights

Organismal survival depends on the balance of substrate flux through energy-generating pathways and the adaptation of these metabolic pathways to environmental changes
Evolution of the Crabtree effect in yeast is associated with the whole genome duplication event (WGD) (Merico et al, 2007), in which many genes duplicated, conferring dosage effects of increased copy number and opportunities for previously shared functions to become split between two genes or new functions to emerge (Chen et al, 2008)
To assess the impact of WGD and pyruvate kinase (PYK) duplication on PYK activity, basal and FBP stimulated PYK activity was compared between pre- and post-WGD yeast species (Figure 1A)

Summary

Introduction

Organismal survival depends on the balance of substrate flux through energy-generating pathways and the adaptation of these metabolic pathways to environmental changes. Glucose is a common energy substrate that can be fermented into lactate/ethanol or metabolized aerobically through mitochondrial respiration. Several observations suggest a relationship between the Crabtree effect and duplication of the pyruvate kinase (PYK) gene. A creative effort to block ethanol production and sustain cell growth using only glucose as a carbon source in yeast that were engineered to produce lipids, through deleting pyruvate decarboxylase (PDC), an enzyme involved in fermentation of pyruvate to ethanol, required simultaneous lossof-function mutations in PYK1 (Yu et al, 2018). Evolution of aerobic fermentation (crabtree effect) in yeast is associated with the whole genome duplication (WGD) event, suggesting that duplication of certain genes may have altered yeast metabolism. The pyruvate kinase (PYK) gene is associated with alterations in cell metabolism, and duplicated during the WGD, generating PYK1 and PYK2. The impact of WGD on PYK activity and role of PYK in yeast metabolism were explored

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Results

Conclusion