| Project/Area Number |
05404079
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Structural biochemistry
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| Research Institution | University of Tokyo |
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Principal Investigator |
SUZUKI Koichi Univ.of Tokyo, Professor Inst.Mol.Cell.,, 分子細胞生物学研究所, 教授 (80011948)
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| Co-Investigator(Kenkyū-buntansha) |
TOMIOKA Shigeo Univ.of Tokyo, Assistant Inst.Mol.Cell.,, 分子細胞生物学研究所, 教務職員 (90159046)
SORIMACHI Hiroyuki Univ.of Tokyo, Lecturer Inst.Mol.Cell.,, 分子細胞生物学研究所, 助手 (10211327)
ISHIURA Shoichi Univ.of Tokyo, Assoc.Prof.Inst.Mol.Cell.,, 分子細胞生物学研究所, 助教授 (10158743)
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| Project Period (FY) |
1993 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥30,300,000 (Direct Cost: ¥30,300,000)
Fiscal Year 1995: ¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1994: ¥9,300,000 (Direct Cost: ¥9,300,000)
Fiscal Year 1993: ¥16,900,000 (Direct Cost: ¥16,900,000)
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| Keywords | caplapin / calcium / proteases / proteolysis / カルパスタチン / カルシユム |
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| Research Abstract |
To clarify further the physiological function of calpain which is thought to play essential roles in various cellular functions mediated by calcium ions, newly identified tissue specific calpains were mainly analyszed and following results were obtained.
1. A novel calpain species specific for smooth muscle and a third ubiquitous chicken calpain were identified and their structures were determined.
2. Skeletal muscle specific caplain, p94, is unstable due to very rapid autocatalytic degradation. This instability was ascribed to a p94-specific in-sertion sequence, IS2. Upon removal of IS2 from p94, p94 became stable and stable m- and -calpain species became unstable upon insertion of IS2.
3.Proteins that interact with p94 were investigated using the yeast two hybrid system. p94 did not interact with the small subunit of calpain (30K) but bound to a giant muscle elastic protein, connectin, indicating that p94 plays a pivo-tal role in skeletal muscle function.
4. Calpain has long been believed to function as a dimer of a large catalytic subunit (80K) and a regulatory subunit (30K). Precise studied on the renaturation of calpain subunits revealed that 80K itself is enzymatically fully active and dissociation of 80K from 30K induced by calcium ions corresponds to activation. 30K not only regulates the calucium sensitivity of 80K but also functions as a chaperonine of 80K and keeps its proper conformation.
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