| Project/Area Number |
12490023
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
広領域
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| Research Institution | Kobe University |
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Principal Investigator |
HAYASHI Fumio Kobe University, Faculty of Science, Dept Biology, Professor, 理学部, 教授 (80093524)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥10,300,000 (Direct Cost: ¥10,300,000)
Fiscal Year 2002: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2001: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2000: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | G protein / phosphorylation / Cdk5 / phosphatase / cell signaling / photoreceptor / raft / detergent-resistant membrane / raft / phosphodiesterase / transducin / G protein / プロテインキナーゼ / 光信号変換 / 網膜 / cGMP / ホスホジエステラーゼ / タンパク質リン酸化 / CdK5 / 光情報変換 / ホスホジェステラーゼ |
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| Research Abstract |
We have investigated the physiological importance of the phosphorylation of an inhibitory subunit of the cGMP-phosphodiesterse (PDE6) in the recovery process of phototransduction in vertebrate photoreceptors. Using in vitro and in situ experimental system, we have clarified that 1) the protein kinase involved in the phosphorylation of the inhibitory subunit of PDE6, i.e. Pγ, is a cyclin-dependent protein kinase 5 in the photoreceptor cells. 2) the phosphorylation occurs when the substrate interacts with the α sub unit of G protein, i.e. transducin. That means the phosphorylation occurs when the PDE is activated. 3) Phosphodiesterase, presumably PP2A, is always in its active state, and is ready for rapid dephosphorylation of Pγ. The importance of our findings is as follows: 1) we clarified a function of Cdk5 in photoreceptor cells, 2) our results revealed that the inactivation of transducin (Gα_t) is not completed with the GTP hydrolysis on Gα_t, but the phosphorylation of Pγ complexed with Gα_t is required. Phosphorylation and dephosphorylation of Pγ by Cdk5 and a phosphatase seem to have important roles in the formation of very sharp pulse response to a weak photosignal.
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