Protein quality control of photosystemI in thylakoid membranes

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K06290
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44030:Plant molecular biology and physiology-related
• Research Institution: Setsunan University (2020); Okayama University (2018-2019)
• Principal Investigator: KATO YUSUKE 摂南大学, 農学部, 講師 (10437569)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 葉緑体 / チラコイド膜 / 光阻害 / タンパク質品質管理 / 光合成

Outline of Final Research Achievements

In the photosynthesis process, two large protein complexes called photosystem I (PSI) and II (PSII) are targets of photo-oxidative damage. The irreversible inactivation of photosynthetic apparatuses causes an inhibitory effect on photosynthesis (termed photoinhibition) and consequently leads to impaired plant growth. Thus, photosynthetic organisms have built sophisticated protein repair mechanisms to avoid photoinhibition.
Compared with the extensive studies on the PSII repair system, the mechanism of photo-oxidative damage and repair on the PSI complex remain to be elucidated. In this study, we analyzed the degradation and the photo-oxidative modifications of the PSI complex proteins. Results show that the specific degradation of PsaC protein binding FeS clusterin PSI. Further study using LC-MS/MS revealed photo-oxidative modifications of Trp and Met in the protein under light-induced stress.

Free Research Field

植物分子・生理科学

Academic Significance and Societal Importance of the Research Achievements

光合成は植物の生長を支えるが、一方で光によるストレスが光合成装置(光合成タンパク質複合体)を損傷している。本研究では光化学系Iの光損傷、その損傷によるタンパク質の傷害のメカニズムを研究し、特定タンパク質が光損傷のターゲットである可能性を見出した。この成果から、多様な光ストレス環境で生きる植物の仕組みを理解し、活用することで、環境ストレス耐性の付与、作物の生育促進といった応用研究の基盤となると期待される。