2007 Fiscal Year Final Research Report Summary
Molecular Mechanism ofTtrapyrrole Distribution and Transportation in Higher Plants
| Project/Area Number |
18570034
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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 | The University of Tokyo |
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Principal Investigator |
MASUDA Tatsuru The University of Tokyo, Graduate School of Arts and Sciences, Associate Professor (00242305)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Tetrapyrrole / heme / chloroplast / carrier protein / oxidative stress / reactive oxvgen species / chemiluminescence |
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| Research Abstract |
In plants, tetrapyrroles are classified into four major groups, chlorophylls, bilins, hemes, and siroheme. These tetrapyrroles are indispensable for various vital activities of plant cells. These tetrapyrroles are synthesized in plastids, subsequently distributed to various organelles. Chlorophylls exist in only plastids, while hemes are required for numerous apo-heme proteins existing in various organelles in the cell. Furthermore, recent studies on retrograde signaling from the chloroplast suggest that some chlorophyll intermediates, such as Mg-protoporphyrin IX and Mg-protoporphyrin IX monomethyl ester, act as signals transferred from plastids to the nucleus to control nuclear-encoded photosynthetic genes. However, the mechanisms of distribution and transportation of these tetrapyrroles in plant cells are not well understood. Since tetrapyrroles are poorly soluble in aqueous solutions under physiological conditions, it is assumed that there must be tetrapyrrole transportation system that are responsible for tetrapyrrole trafficking in the plant cell.
In this research project, to clarify the molecular mechanism of tetrapyrrole distribution and transportation in higher plants, we first developed extremely sensitive heme assay by reconstitution with horseradish peroxidase apo-enzyme, which allows to detect effused heme from plastids. We then performed biochemical characterization of Arabidopsis cytosolic heme-binding proteins (cHBPs) homologous to the p22HBP/SOUL family. Furthermore, we clarified the redox-dependent regulation of Mg-chelatase via chloroplast thioredoxins, whish is responsible for production of retrograde signals, Mg-protoporphyrin IX.
These contributions significantly enhanced our understandings of regulations and functions of tetrapyrroles in plant cells.
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Research Products
(51 results)
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[Journal Article] Induction of isoforms of tetrapyrrole biosynthetic enzymes, atHEMA2 and atFC1, under stress conditions and their physiological functions in Arabidopsis thaliana2007
Author(s)
Nagai S, Koide M, Takahashi S, Kikuta A, Aono M, Sasaki-Sekimoto Y, Ohta H, Takamiya K, Masuda T
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Journal Title
Plant Physiology 144
Pages: 1039-1051
Description
「研究成果報告書概要(和文)」より
Peer Reviewed
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[Book] 光合成の科学2007
Author(s)
東京大学光合成教育研究会(池内昌彦, 佐藤直樹, 園池公毅, 田中寛, 箸本春樹, 増田建, 村田滋, 和田元)
Total Pages
291
Publisher
東京大学出版会
Description
「研究成果報告書概要(和文)」より
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[Book] Kougousei no kagaku2007
Author(s)
Ikeuchi M, Sato N, Sonoike K, Tanaka K, Hashimoto H, Masuda. T, Murata A, Wada H
Publisher
University of Tokyo Press
Description
「研究成果報告書概要(欧文)」より
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