2021 Fiscal Year Final Research Report
New regulatory mechanisms of cellular Ca2+ signaling by chloroplasts
| Project/Area Number |
17H03968
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied molecular and cellular biology
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| Research Institution | Setsunan University (2020-2021)
Kyoto Prefectural University (2017-2019) |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
野村 裕也 岐阜女子大学, 家政学部, 准教授 (00547028)
熊崎 茂一 京都大学, 理学研究科, 准教授 (40293401)
石崎 陽子 摂南大学, 農学部, 助手 (50423869)
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| Project Period (FY) |
2017-04-01 – 2021-03-31
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| Keywords | 葉緑体 / ミトコンドリア / Ca2+ / ROS / シグナル伝達 / ストレス応答 / 気孔 |
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| Outline of Final Research Achievements |
In mammalian cells, mitochondria play a vital role in maintaining intracellular calcium(Ca2+) homeostasis. In contrast, the role of symbiotic organelles such as chloroplasts and mitochondria in plant cellular Ca2+ signaling remains elusive. In this study, we characterized two chloroplast-localized Ca2+-binding proteins CAS and CRSH. We found that light-dependent phosphorylation of CAS mediated by thylakoid protein kinase STN8 is critical for the light-induced opening of stomata. In addition, CRSH is responsible for the darkness-induced accumulation of (p)ppGpp, which is necessary to downregulate some plastidial gene expression. Furthermore, we found that chloroplast-localized mechano-sensitive channels are involved in the regulation of cellular ROS localization. Moreover, we found that mitochondrial dysfunction leads to the generation of a cytosolic Ca2+ transient and subsequent activation of Ca2+-dependent stress gene expression.
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| Free Research Field |
植物分子生理学
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| Academic Significance and Societal Importance of the Research Achievements |
植物の環境応答やストレス応答で、細胞内のCa2+シグナルと活性酸素種（ROS) シグナルは相互に作用しながら重要なシグナル伝達の役割を果たしている。植物細胞には葉緑体やミトコンドリアなどの細胞小器官が存在し、細胞質との間でCa2+やROS信号の伝達をしていると考えられるが、その分子機構はわかっていない。本研究では、葉緑体内でCa2+やROSシグナルに関わる遺伝子の機能を解析し明らかにした。また、ミトコンドリアによるCa2+シグナル制御の可能性も示した。
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