| Project/Area Number |
13670045
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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 |
General physiology
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| Research Institution | Kagoshima University |
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Principal Investigator |
KAMEYAMA Masaki Kagoshima University, Faculty of Medicine, Professor, 医学部, 教授 (60150059)
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| Co-Investigator(Kenkyū-buntansha) |
YAZAWA Kazuto Kagoshima University, Faculty of Medicine, Assistant Professor, 医学部, 講師 (90212274)
HAO Li-ying Kagoshima University, Faculty of Medicine, Research Associate, 医学部, 助手 (40311881)
KAMEYAMA Asako Kagoshima University, Faculty of Medicine, Assistant Professor, 医学部, 講師(現非常勤) (70244225)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2002: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2001: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Calcium channel / ion channel / patch clamp / cardiac myocyte / Caチャンネル / イオンチャンネル |
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| Research Abstract |
L-type Ca channels are present in many cell types and control various cellular functions. A unique feature of L-type Ca channels is 'run-down' phenomenon, which is prominent in cell-free patch-clamp experiments, in this study, we tested the hypothesis that 'run-down' might be caused by a loss of unknown regulatory factor(s) in cytoplasm. In addition, we also explored phosphorylation site(s) of the channel catalyzed by protein kinase A (PKA) and possible interactions between the actions mediated by cytoplasmic factors and PKA. Electrophysiological experiments were carried out in guinea-pig ventricular myocytes or in cultured BHK cells expressing guinea-pig Ca channels, using patch-clamp method. Results: 1)One factor appreared at Mr' of 250-300k on gel filtration, and suggested to be calpastatin. Another factor (H factor) appeared at Mr' of >300k on gel filtration, and was eluted by KCl of 180-360 mM. 2)Calpstatin interacted with a fragment of C-terminal region of the channel in surface prasmon resonance (SPR) analysis. 3)Substitution by alanin of Ser1574 or Sen1927, located in the C-terminal tail of the channel, affected the up-modulation of channel activity by PKA. These results suggest that L-type Ca channel is regulated by cytoplasmic factors and PKA, and that the C-terminal tail of the channel is involved in these regulatory mechanisms.
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