| Project/Area Number |
13680691
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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 |
Structural biochemistry
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| Research Institution | The University of Tokushima |
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Principal Investigator |
OBATA Toshiyuki The University of Tokushima, Institute for Enzyme Research, Research Associate, 分子酵素学研究センター, 助手 (40325296)
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| Co-Investigator(Kenkyū-buntansha) |
YUASA Tomoyuki The University of Tokushima, Institute for Enzyme Research, Research Associate, 分子酵素学研究センター, 助手 (50304556)
EBINA Yousuke The University of Tokushima, Institute for Enzyme Research, Professor, 分子酵素学研究センター, 教授 (00112227)
TANIGUCHI Hisaaki The University of Tokushima, Institute for Enzyme Research, Professor, 分子酵素学研究センター, 教授 (10257636)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2002: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2001: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | insulin action / diabetes / Akt / proteomics / インスリン / リン酸化タンパク質 / プロテオーム解析 |
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| Research Abstract |
Insulin plays a central role in the regulation of glucose homeostasis in part by stimulating glucose uptake and glycogen synthesis. The serine/threonine protein kinase Akt has been proposed to mediate insulin signaling in several processes. However, it is unclear if Akt is involved in insulin-stimulated glucose uptake, and whether which isoforms of Akt are responsible for each insulin action. We confirmed that expression of a constitutively active Akt, using an adenoviral expression vector promoted translocation of glucose transporter 4 (GLUT4) to plasma membrane, 2-deoxyglucose (2-DG) uptake and glycogen synthesis in both Chinese hamster ovary (CHO) cells and 3T3-L1 adipocytes. Inhibition of Akt either by adenoviral expression of a dominant-negative Akt or by the introduction of synthetic 21-mer short-interference RNA (siRNA) against Akt markedly reduced insulin-stimulated GLUT4 translocation, 2-DG uptake and glycogen synthesis. Experiments with isoform-specific siRNA revealed that Akt2, and Akt1 to lesser extent, has an essential role in insulin-stimulated GLUT4 translocation and 2-DG uptake in both cell lines, while Akt1 and Akt2 contribute equally to insulin-stimulated glycogen synthesis. These data suggest a prerequisite role of Akt in insulin-stimulated glucose uptake and distinct functions among Akt isoforms.
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