2021 Fiscal Year Final Research Report

Understanding of reactive nitrogen species-dependent signal transduction in yeast by comprehensive and quantitative analysis methods

Research Project

PDF

Project/Area Number	19K16129
Research Category	Grant-in-Aid for Early-Career Scientists
Allocation Type	Multi-year Fund
Review Section	Basic Section 44010:Cell biology-related
Research Institution	Nara Institute of Science and Technology
Principal Investigator	Nasuno Ryo 奈良先端科学技術大学院大学, 先端科学技術研究科, 助教 (90708116)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	翻訳後修飾 / 一酸化窒素 / 酵母 / 代謝 / ニトロ化 / グルタチオン化
Outline of Final Research Achievements	My proteomic and biochemical analyses identified pyruvate decarboxylase Pdc1 as a nitrated protein. Nitration at Tyr157 and Tyr344 decreased the enzymatic activity of Pdc1. Further analyses showed that reactive nitrogen species (RNS) suppress the fermentation efficiency through the inhibition of Pdc1 by its nitration at Tyr157 and Try344. I also demonstrated that fructose-1,6-bisphosphate aldolase Fba1 was S-glutathionylated at Cys112, which inhibits the enzymatic activity of Fba1, in response to RNS. My metabolite quantification suggested that S-glutathionylation of Fba1 increased the intracellular NADPH, via the metabolic shift from glycolysis to pentose phosphate pathway. Furthermore, My cell viability assay showed that S-glutathionylation of Fba1 contributed to RNS tolerance in yeast. These results suggest that yeast protects cells from RNS stress by the increased NADPH via the metabolic shift induced by S-glutathionylation of Fba1.
Free Research Field	応用微生物学
Academic Significance and Societal Importance of the Research Achievements	本研究では、RNSストレス環境下で酵母のPdc1がニトロ化され、発酵力が抑制されることを見出した。発酵生産過程では、安価な炭素源である廃糖蜜が含有する亜硝酸塩がRNSを発生すること、発酵が阻害されることが知られている。本研究の成果は、発酵生産過程における発酵力阻害の分子機構を明らかにしたものであり、発酵産業への応用が期待できる。一方、Fba1のS-グルタチオン化が、代謝フローの改変を介してRNSストレス耐性に寄与する機構は、これまでに報告が無い。また、活性中心以外のCys残基のS-グルタチオン化が酵素活性を抑制する現象も、全く新たな知見であり、RNS依存的翻訳後修飾の更なる理解に資する。