Investigation for the physiological role of amino acid recycle from vacuoles during autophagy by elucidating the mechanism of vacuolar amino acid export

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05560
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38060:Applied molecular and cellular biology-related
• Research Institution: Ehime University
• Principal Investigator: Sekito Takayuki 愛媛大学, 農学研究科, 教授 (20419857)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 液胞 / オートファジー / Saccharomyces cerevisiae / トランスポーター / TORC1

Outline of Final Research Achievements

In this research, we identified Ypq2, which mediates the arginine/histidine exchange across the vacuolar membrane, and Vsb1, which is involved in the uptake of basic amino acids into vacuoles. We also revealed that Stm1, a Ypq2 homolog in the fission yeast, is functionally conserved. In addition, the expression of AVT4 and AVT6, both of which are transporters to export amino acids from vacuoles, were shown to be directly regulated at the transcriptional level by the GATA transcription factors. Since the GATA transcription factors play a central role in the adaptation of cellular amino acid metabolism in response to the changes in environmental nitrogen availability, our results strongly suggest that the vacuolar amino acid transport system contributes to the cellular amino acid homeostasis.

Free Research Field

細胞生物学

Academic Significance and Societal Importance of the Research Achievements

細胞内のアミノ酸ホメオスタシスは細胞の適正な成長・増殖を維持するとともに、ストレス時の生存にも必須である。液胞／リソソームはその中で重要な役割を担うと考えられている。本研究でのYpq2とVsb1の同定解析で得られた知見はその分子機構の解明に大きく貢献する。また、本研究を含めこれまでの研究により、液胞アミノ酸トランスポーターの同定が大きく進捗した。本研究ではトランスポーター欠損による生育表現型や活性調節に関する知見も得られており、液胞内アミノ酸の生理機能解明への突破口になると考えられる。