| Project/Area Number |
02454132
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
General pharmacology
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| Research Institution | Gunma University School of Medicine |
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Principal Investigator |
KOHAMA Kazuhiro Gunma University School of Medicine, Department of Pharmacology, Professor, 医学部, 教授 (30101116)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIKAWA Ryoki Gunma University School of Medicine, Department of Pharmacology, Research Associ, 医学部, 助手 (20212863)
赤木 宏行 群馬大学, 医学部, 講師
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 1991: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1990: ¥3,400,000 (Direct Cost: ¥3,400,000)
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| Keywords | myosin / Calcium / kinase / myosin light chain / myosin heavy chain / physarum polycephalum / アクチン / 細胞内情報伝達 |
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| Research Abstract |
ATP-dependent interactions between myosin and actin in the lower eucaryote, Physarum polycephalum, are inhibited by micromolar levels of Ca^<2+>. This inhibition is mediated by the binding of Ca^<2+> to myosin, the phosphorylation of which is required if Ca^<2+> is to inhibit the activities of myosin. As the first step to examine whether Ca^<2+> also regulates phosphorylation in the actomyosin system, we purified myosin light chain kinase (MLCK) of 55 kDa almost to homogeneity. The MLCK activity was high whether or not Ca^<2+> was present. A Ca^<2+>-dependent inhibitory factor (CIF) of 38 kDa was purified from Physarum. We showed that CIF was effective to reduce the MLCK activity in a Ca^<2+>-dependent manner.
Using crude preparations, not only MLCK but also myosin heavy chain kinase and actin kinase were shown to be inhibited by Ca^<2+> half-maximally at micromolar levels. Since CIF is the only Ca^<2+>-binding protein in the preparations, we propose that this inhibitory Ca^<2+>-regulation of the kinases for actomyosin is mediated by CIF.
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