2006 Fiscal Year Final Research Report Summary
Regulation of plant metabolic function mediated by protein S-nitrosylation
| Project/Area Number |
17570039
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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 | HIROSHIMA UNIVERSITY |
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Principal Investigator |
SAKAMOTO Atsushi Hiroshima University, Graduate School of Science, Professor, 大学院理学研究科, 教授 (60270477)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Protein S-nitrosylation / Reactive nitrogen species (RNS) / S-nitrosothiol / S-nitrosoglutathione (GSNO) / GSNO reductase / Nitrate assimilation / NO signaling / Arabidopsis |
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| Research Abstract |
S-Nitrosylation of cysteine residues is a critical redox modification that regulates a broad spectrum of protein functions, and this process involves reactive nitrogen species (RNS) such as S-nitrosothiols (RSNO) that are known to modify the thiol moiety of proteins. This research attempted to examine: (1) the importance of RSNO metabolism in modulating protein S-nitrosylation in higher plants, with special focus on the regulatory role of S-nitrosoglutathione reductase (GSNOR) as a key enzyme determining cellular RSNO levels and the degree of S-nitrosylation; and (2) the possibility that this posttranslational modification may participate in the regulation of certain plant metabolic functions such as nitrogen assimilation.
(1) When exposed to RNS such as NO_2, NO donors and nitrate, Arabidopsis plants increased the level of RSNO, a substantial proportion of which was recovered in high-molecular fractions. This suggests the proteinous nature of accumulated RSNO in response to these inorg
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anic nitrogen oxides. Using biotin-switch method, the changes in S-nitrosylated protein levels were monitored and it was found that NO-donor treatments enhanced protein S-nitrosylation in wild-type plants. Overexpression of GSNOR, however, alleviated the extent of this posttranslational modification, with the increased level much lower than that seen in wild-type plants, supporting the importance of this enzyme in modulating protein S-nitrosylation.
(2) The physiological consequence of GSNOR overexpression was investigated with respect to the regulatory aspects of nitrogen assimilation. When fed with a single ^<15>N-labeled nitrogen source such as nitrate or NO_2, transgenic plants overexpressing GSNOR incorporated and assimilated more nitrate-and NO_2-derived ^<15>N than did the wild-type plants. Because GSNOR is catalytically not related to the assimilatory process of inroganic nitrogen, these results suggest the possible involvement of GSNOR, and hence S-nitrosylation of proteins, in the regulation of nitrogen assimilation. Less
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Research Products
(22 results)
