2007 Fiscal Year Final Research Report Summary
Molecular properties of metal-uptake systems supported by proton pumps in plant cells
| Project/Area Number |
18380064
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied biochemistry
|
|---|
| Research Institution | Nagoya University |
|---|
Principal Investigator |
MAESHIMA Masayoshi Nagoya University, Graduate School of Bioagricultural Sciences, Professor (80181577)
|
|---|
| Project Period (FY) |
2006 – 2007
|
| Keywords | Metal ion / Accumulation into vacuole / Zinc transporter / Metal-binding protein / Proton pump |
|---|
| Research Abstract |
We obtained the following results concerning Ca^<2+>/H^+ exchanger, Zn^<2+>/H^+ exchanger, metal-binding protein, proton pumps in the vacuolar membranes in this project.
(1) Cation/H^+ exchangers: Rice has five isoforms of cation/H^+ exchanger (CAX). CAX1a among five isoforms is expressed in all tissues examined and is highly expressed in companion and endodermis cells, which has high concentration of Ca^<2+>. We estimate that CAX1a functions to reserve Ca^<2+> into vacuoles and is involved in the Ca^<2+> detoxification.
(2) Novel metal binding protein (PCaP1): We found a novel metal cation-binding protein, AtPCaP1, in Arabidopsis thaliana. The protein is N-myristoylated and stably associated with the plasma membrane in vitro and in vivo. AtPCaP1 binds to Ca^<2+>, Cu^<2+>, Ca^<2+>/calmodulin complex, and phosphatidylinositol phosphates. From these biochemical properties, we estimate that the protein is involved in signal transduction of environmental stresses, such as metal and pathogen stresses.
(3) Vacuolar zinc transporter (MTP1): Arabidopsis MTP1 has been demonstrated to be located to the vacuolar membrane. The knockout mutant of MTP1 was highly sensitive to high concentrations (more than 0.2 mM) of zinc. Thus, MTP1 might be involved in the Zn detoxification by transport of the excess Zn^<2+> ion in the cytoplasm into vacuoles. By heterologous expression of MTP1 in yeast and direct measurement of zinc transport using Zn-65, we demonstrated that MTP1 functions as Zn^<2+>/H^+ exchanger. Furthermore, we found that the cytoplasmic histidine-rich region functions as a buffering pocket of Zn2+ and a sensor of the zinc level at the cytoplasmic surface.
(4) Vacuolar proton pump: Vacuolar membrane H^+-pyrophosphatase (H^+-PPase) acidifies vacuoles and maintains the pH gradient across the membrane. We determined the essential residues and functional motifs in the enzyme.
|
-
-
-
-
-
-
-
-
-
[Journal Article] Characterization of a tobacco TPK-type K^+ channel as a novel tonoplast K^+ channel using yeast tonoplast.2008
Author(s)
Hamamoto, S., Marui, J., Matsuoka, K., Higashi, K., Igarashi, K., Nakagawa, T., Mori, Y, Murata, Y., Nakanishi, Y, Maeshima, M., Yabe, I., Uozumi, N.
-
Journal Title
Journal of Biological Chemistry 283
Pages: 1911-1920
Description
「研究成果報告書概要(欧文)」より
-
-
-
-
-
[Journal Article] The ABC transporter AtABCB14 is a malate importer and modulates stomatal response to CO2.2008
Author(s)
Lee, M., Choi, Y, Burla, B., Kim, Y.-Y, Jeon, B., Maeshima, M., Yoo, J.-Y, Martinoia, M., Lee, Y
-
Journal Title
Nature Cell Biology 10
Pages: 1217-1223
Description
「研究成果報告書概要(欧文)」より
-
-
-
-
-
-
-
-
-
[Journal Article] Transcriptional induction of two genes for CCaPs, novel cytosolic proteins, in Arabidopsis thaliana in the dark2007
Author(s)
Ide, Y, Tomioka, R., Ouchi, Y, Kamiya, T., Maeshima, M.
-
Journal Title
Plant and Cell Physiology 48
Pages: 54-65
Description
「研究成果報告書概要(欧文)」より
-
-
-
-
[Journal Article] properties of novel, hydrophilic cation-binding proteins associated with the plasma membrane.2007
Author(s)
Ide, Y, Nagasaki, N., Tomioka, R., Suito, M., Kamiya, T., Maeshima, M.
-
Journal Title
Journal of Experimental Botany 58
Pages: 1173-1183
Description
「研究成果報告書概要(欧文)」より
-
-
-
-
-
-
-
-
-
-
-
[Journal Article] Disruption of AtPDR8, a plasma membrane ABC transporter of Arabidopsis, exhibits hypersensitive cell death by pathogen infection.2006
Author(s)
Kobae, Y, Yoshioka, H., Sekino, T., Nakagawa, T., Martinoia, E., Maeshima, M.
-
Journal Title
Plant and Cell Physiology 47
Pages: 309-318
Description
「研究成果報告書概要(欧文)」より
-
-
-
-
[Presentation] Functional structure of H*pump pyrophosphatase that uses a low cost substrate.2007
Author(s)
Hirono, M., Mimura, H., Segami, S., Nakanishi, Y., Maeshima, M.
Organizer
International Symposium on Membrane Transport as a Universal Biological Mechanism.
Place of Presentation
Kyoto, Japan.
Year and Date
20070113-20070114
Description
「研究成果報告書概要(欧文)」より
-
-
