Affordable Access

deepdyve-link
Publisher Website

Nutrient Signaling via the TORC1-Greatwall-PP2AB55δ Pathway Is Responsible for the High Initial Rates of Alcoholic Fermentation in Sake Yeast Strains of Saccharomyces cerevisiae.

Authors
  • Watanabe, Daisuke1, 2
  • Kajihara, Takuma3
  • Sugimoto, Yukiko3
  • Takagi, Kenichi3
  • Mizuno, Megumi2
  • Zhou, Yan2
  • Chen, Jiawen4
  • Takeda, Kojiro5, 6
  • Tatebe, Hisashi3
  • Shiozaki, Kazuhiro3
  • Nakazawa, Nobushige7
  • Izawa, Shingo8
  • Akao, Takeshi2
  • Shimoi, Hitoshi2, 9
  • Maeda, Tatsuya4
  • Takagi, Hiroshi3
  • 1 Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan [email protected] , (Japan)
  • 2 National Research Institute of Brewing, Higashihiroshima, Hiroshima, Japan. , (Japan)
  • 3 Division of Biological Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara, Japan. , (Japan)
  • 4 Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan. , (Japan)
  • 5 Department of Biology, Faculty of Science and Engineering, Konan University, Kobe, Japan. , (Japan)
  • 6 Institute for Integrative Neurobiology, Konan University, Kobe, Japan. , (Japan)
  • 7 Department of Biotechnology, Faculty of Bioresource Science, Akita Prefectural University, Akita, Akita, Japan. , (Japan)
  • 8 Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto, Japan. , (Japan)
  • 9 Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan. , (Japan)
Type
Published Article
Journal
Applied and Environmental Microbiology
Publisher
American Society for Microbiology
Publication Date
Jan 01, 2019
Volume
85
Issue
1
Identifiers
DOI: 10.1128/AEM.02083-18
PMID: 30341081
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

Saccharomyces cerevisiae sake yeast strain Kyokai no. 7 (K7) and its relatives carry a homozygous loss-of-function mutation in the RIM15 gene, which encodes a Greatwall family protein kinase. Disruption of RIM15 in nonsake yeast strains leads to improved alcoholic fermentation, indicating that the defect in Rim15p is associated with the enhanced fermentation performance of sake yeast cells. In order to understand how Rim15p mediates fermentation control, we here focused on target-of-rapamycin protein kinase complex 1 (TORC1) and protein phosphatase 2A with the B55δ regulatory subunit (PP2AB55δ), complexes that are known to act upstream and downstream of Rim15p, respectively. Several lines of evidence, including our previous transcriptomic analysis data, suggested enhanced TORC1 signaling in sake yeast cells during sake fermentation. Fermentation tests of the TORC1-related mutants using a laboratory strain revealed that TORC1 signaling positively regulates the initial fermentation rate in a Rim15p-dependent manner. Deletion of the CDC55 gene, encoding B55δ, abolished the high fermentation performance of Rim15p-deficient laboratory yeast and sake yeast cells, indicating that PP2AB55δ mediates the fermentation control by TORC1 and Rim15p. The TORC1-Greatwall-PP2AB55δ pathway similarly affected the fermentation rate in the fission yeast Schizosaccharomyces pombe, strongly suggesting that the evolutionarily conserved pathway governs alcoholic fermentation in yeasts. It is likely that elevated PP2AB55δ activity accounts for the high fermentation performance of sake yeast cells. Heterozygous loss-of-function mutations in CDC55 found in K7-related sake strains may indicate that the Rim15p-deficient phenotypes are disadvantageous to cell survival.IMPORTANCE The biochemical processes and enzymes responsible for glycolysis and alcoholic fermentation by the yeast S. cerevisiae have long been the subject of scientific research. Nevertheless, the factors determining fermentation performance in vivo are not fully understood. As a result, the industrial breeding of yeast strains has required empirical characterization of fermentation by screening numerous mutants through laborious fermentation tests. To establish a rational and efficient breeding strategy, key regulators of alcoholic fermentation need to be identified. In the present study, we focused on how sake yeast strains of S. cerevisiae have acquired high alcoholic fermentation performance. Our findings provide a rational molecular basis to design yeast strains with optimal fermentation performance for production of alcoholic beverages and bioethanol. In addition, as the evolutionarily conserved TORC1-Greatwall-PP2AB55δ pathway plays a major role in the glycolytic control, our work may contribute to research on carbohydrate metabolism in higher eukaryotes. Copyright © 2018 American Society for Microbiology.

Report this publication

Statistics

Seen <100 times