| Project/Area Number |
06304006
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 総合 |
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| Research Field |
動物生理・代謝
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| Research Institution | University of Tokyo |
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Principal Investigator |
KAMIYA Ritsu University of Tokyo, Graduate School of Science, Professor, 大学院・理学系研究科, 教授 (10124314)
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| Co-Investigator(Kenkyū-buntansha) |
NOGUCHI Munenori Toyoma University Faculty of Science, Associate Professor, 理学部, 助教授 (30019004)
OGAWA Kazuo National Institute for Basic Biology, Associate Professor, 基礎生物学研究所, 助教授 (30132731)
BABA Akitsugu Ochanomizu Women's College, Faculty of Science, Professor, 理学部, 教授 (80011691)
TAKAHASHI Keiichi International Christian Univ. Dept. of General Education, Professor, 教養学部, 教授 (40011481)
MOHRI Hideo National Institure for Basic Biology, Director General, 基礎生物学研究所, 所長 (70012268)
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| Project Period (FY) |
1994 – 1996
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| Keywords | cilia / flagella / dynein / microtubule / calcium / cyclic AMP / cell movement / sperm |
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| Research Abstract |
This research has been aimed at the elucidation of the molecular mechanism that generates and controls flagellar and ciliary movements. The beating of flagella and cilia is based on the sliding movement between adjacent microtubules, driven by dynein arms. Through examination of the structure of dynein arms and properties of the sliding movement, we obtained the following important findings : 1) Outer dynein arms in multicellular organisms always contain two heavy chains, whereas those in unicellular organisms have three heavy chains ; 2) The three intermediate chains in the outer arm dynein have enzyme activities involved in nucleotide metabolism ; 3) Inner arm dynein contains true actin as a subunit ; 4) The activity of dynein function may be regulated through nucleotide binding to multiple sites in the dynein heavy chain ; 5) Dynein itself may have a nature to produce oscillatory movements. 6) Outer arm dynein and inner arm dynein appears to have different properties of force production. Regarding the regulation of ciliary and flagellar movements, we examined the effect of protein phosphorylation and calcium ion. We first obtained evidence that the site of phosphorylation-based regulation in mammalian sperm fagella is located at their bases ; protein phosphorylation at the base appears to regulate whether the flagella initiate beating. In Paramecium cilia, Phosphorylation appears to modulate the sensitivity to calcium. Thus, ciliary movements appear to be regulated by the coordination of calcium ion and protein phosphorylation. In beating sea urchin sperm axonemes, microtuble sliding is apparently regulated by calcium ion. However, the velocity of microtubule sliding under load-free conditions is not affected by calcium. Thus, calcium ion appears to regulate the force generation, possibly by regulating the number of active dynein arms. How calcium regulates the activity of dynein remains an important future problem.
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