title: Spatial reorganization of Saccharomyces cerevisiae enolase to alter carbon metabolism under hypoxia.
abstract: Hypoxia has critical effects on the physiology of organisms. In the yeast Saccharomyces cerevisiae, glycolytic enzymes, including enolase (Eno2p), formed cellular foci under hypoxia. Here, we investigated the regulation and biological functions of these foci. Focus formation by Eno2p was inhibited temperature independently by the addition of cycloheximide or rapamycin or by the single substitution of alanine for the Val22 residue. Using mitochondrial inhibitors and an antioxidant, mitochondrial reactive oxygen species (ROS) production was shown to participate in focus formation. Focus formation was also inhibited temperature dependently by an SNF1 knockout mutation. Interestingly, the foci were observed in the cell even after reoxygenation. The metabolic turnover analysis revealed that [U-(13)C]glucose conversion to pyruvate and oxaloacetate was accelerated in focus-forming cells. These results suggest that under hypoxia, S. cerevisiae cells sense mitochondrial ROS and, by the involvement of SNF1/AMPK, spatially reorganize metabolic enzymes in the cytosol via de novo protein synthesis, which subsequently increases carbon metabolism. The mechanism may be important for yeast cells under hypoxia, to quickly provide both energy and substrates for the biosynthesis of lipids and proteins independently of the tricarboxylic acid (TCA) cycle and also to fit changing environments.
authors.affiliation: Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Natsuko
authors.initials: N
authors.lastname: Miura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Shinohara
authors.forename: Yohei
authors.initials: Y
authors.lastname: Tatsukami
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Sato
authors.forename: Hironobu
authors.initials: H
authors.lastname: Morisaka
authors.forename: Kouichi
authors.initials: K
authors.lastname: Kuroda
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Ueda
mesh_terms: D002244:Carbon / Q000378:metabolism*; D015687:Cell Hypoxia; D002952:Citric Acid Cycle; D003600:Cytosol / Q000201:enzymology; D008928:Mitochondria / Q000378:metabolism*; D010751:Phosphopyruvate Hydratase / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism*
chemical_list: D017382:Reactive Oxygen Species; D002244:Carbon; C071570:SNF1-related protein kinases; D017346:Protein Serine-Threonine Kinases; D010751:Phosphopyruvate Hydratase