2006 Fiscal Year Final Research Report Summary
Research on the mechanism of chloroplast movement
| Project/Area Number |
17570042
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
植物生理・分子
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| Research Institution | Tokyo Metropolitan University |
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Principal Investigator |
KADOTA Akeo Tokyo Metropolitan University, Department of Biological Sciences, Associate Professor (60152758)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Chloroplast movement / Actin filament / Photomovment / Phototropin / Arabiodopsis / GFP |
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| Research Abstract |
Organelle motility is essential for all cells to accomplish efficient and stable cellular functions. Chloroplast movement is representative of organelle motility in plant cells. According to their ambient light, chloroplasts relocate within cells to maximize light capture for photosynthesis and to avoid photodamage under excess light. These movements are regulated by blue light receptors, phototropinl and 2 (phot1, phot2) and depend on actin filaments. However, the molecular mechanisms underlying movement remain to be elucidated. In this research, we showed that chloroplasts utilize a unique actin-based movement mechanism. In vivo imaging of actins in Arabidopsis plants reveals that short actins located at the chloroplast periphery (designated as cp-actin) are responsible for chloroplast photorelocation. In response to blue light, cp-actins become relocalized at the leading edge of chloroplasts prior to movement. By contrast, cp-actins reside around the chloroplast periphery when stationary, thereby anchoring the chloroplast to a particular site within the cell. Mutant analyses indicate that phototropins regulate biased cp-actin relocalization. Our findings demonstrate the presence of a novel actin-based movement machinery in plant cells that is distinct to those found in animals and microorganisms.
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