2006 Fiscal Year Final Research Report Summary
Functional analysis of secretary system in plant cell
| Project/Area Number |
17570035
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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 | Kyoto University |
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Principal Investigator |
SHIMADA Tomoo Kyoto University, Graduate School of Science, Assistant Professor, 大学院理学研究科, 助手 (20281587)
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| Project Period (FY) |
2005 – 2006
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| Keywords | protein storage vacuole / vesicle transport / mutant / Arabidopsis thaliana / vacuolar sorting receptor / storage protein |
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| Research Abstract |
Seed storage proteins are synthesized on the endoplasmic reticulum (ER) as precursors and then transported to protein storage vacuoles, where they are processed into mature forms. We previously reported an Arabidopsis mutant, atvsr1, that abnormally accumulated the precursors of storage proteins. In this study, we identified several mutant that exhibited sorting defects of storage proteins as atvsr1 mutant.
maigo 1 (mag1) abnormally accumulated the precursors of two major storage proteins, 12S globulin and 2S albumin, in dry seeds. Electron microscopy revealed that magi seeds mis-sort storage proteins by secreting them from cells. magi seeds have smaller protein storage vacuoles in the seeds than do wild-type seeds. The MAG1 gene encodes a homolog of the yeast (Saccharomyces cerevisiae) protein VPS29. VPS29 is a component of a retromer complex for recycling a vacuolar sorting receptor VPS10 from the pre-vacuolar compartment to the Golgi complex. Our findings suggest that MAG1/AtVPS29 protein is involved in recycling a plant receptor for the efficient sorting of seed storage proteins.
maigo2 (mag2) seed cells contained many novel structures, with an electron-dense core that was composed of the precursor forms of 2S albumin. 12S globulins were segregated from 2S albumin and were localized in the matrix region of the structures together with the ER chaperones lumenal binding protein and protein disulfide isomerase, which were more abundant in mag2 seeds. The MAG2 gene was identified as At3g47700, and the MAG2 protein had a RINT-1/TIP20 domain in the C-terminal region. We found that some MAG2 molecules were peripherally associated with the ER membrane. MAG2 had an ability to bind to two ER-localized t-SNAREs (for target-soluble NSF [N-ethylmaleimide-sensitive fusion protein] attachment protein receptor; At Sec20 and At Ufe1). Our findings suggest that MAG2 functions in the transport of storage protein precursors between the ER and Golgi complex in plants.
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Research Products
(8 results)
