| Project/Area Number |
12680637
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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 |
Functional biochemistry
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| Research Institution | Kagawa Medical University |
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Principal Investigator |
TOKUMITSU Hiroshi Kagawa Medical University, Medicine, Associate Professor, 医学部, 助教授 (20237077)
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| Co-Investigator(Kenkyū-buntansha) |
KIMURA Yoshishige Helix Research Institute, 3rd Department, Researcher, 第3研究部門, 研究員
KOBAYASHI Ryoji Kagawa Medical University, Medicine, Professor, 医学部, 教授 (00020917)
MURAO Koji Kagawa Medical University, University Hospital, Assistant Professor, 医学部・附属病院, 助手 (20291982)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2000: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | Intracellalr Calcium / Calmodulin / CaM-KK / Sgnal Transduction / Protein Kinase cascade / CREB / C.elegans / CaM-kinase / 細胞内カルシウム |
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| Research Abstract |
Ca^<2+>/calmodulin-dependent protein kinases (CaM-Ks) constitute a diverse group of enzymes, which are involved in many cellular responses mediated by an increase in the concentration of intracellular calcium. Previous studies have demonstrated that two multifunctionla CaM-kinases, CaM-KI and IV, are activated byphosphorylation of an activation loop Thr residue by an upstream CaM-kinase (CaM-KK) resulting in a large increase in catalytic efficiency. In this study, we have found that Ile441 in CaM-KKα is essential for the autoinhibition of CaM-KK and the binding orientation of CaM to CaM-KKα is not critical for relief of the autoinhibition. The unique binding orientation of CaM to CaM-KKα which was originally discovered using NMR analysis, was also confirmed with C.elegans CaM-KK by using X-ray crystallography. In contrast to CaM-KKα, CaM-KKβ-isoform has shown to exhibit enhanced Ca^<2+>/CaM-independent activity which is due to the second regulatory domain (residues 129-151) located in N-terminal of the catalytic domain. This domain inhibits the autoinhibition of CaM-KKβ resulting in generation of its autonomous activity. We also have generated C.elegans carrying CRE-GFP reporter gene and cloned C.elegans CREB. C.elegans CREB-mediated gene expression was induced by C.elegans CaM-K cascade (CaM-KK/CaM-KI) in transfected cells. In living worm, GFP-expression was induced by overexpression of C.elegans CaM-KI 1-295 (constitutively active mutant) in some neurons, which was not observed in CREB-deficient worm. This indicates that CaM-K cascade mediats CREB-dependent transcriptional activation is conserved in C.elegans.
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