| Project/Area Number |
10670658
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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 |
Circulatory organs internal medicine
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| Research Institution | Tottori University Faculty of Medicine |
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Principal Investigator |
CHIAKI Shigemasa Tottori University, The 1st Department of Internal Medicine, Professor, 医学部, 教授 (50111125)
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| Co-Investigator(Kenkyū-buntansha) |
TANIGUCHI Shinichi Tottori University, The 1st Department of Internal Medicine, Clinical and Research Associate, 医学部, 助手 (30304207)
UETA Yoshihiko Tottori University, The 1st Department of Internal Medicine, Associate Professor, 医学部・附属病院, 講師 (80283993)
HISATOME Ichiro Tottori University, The 1st Department of Internal Medicine, Associate Professor, 医学部, 助教授 (60211504)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1999: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | long QT / ubiquitin / proteasome / ATP-sensitive K channel / proteolysis / プロテアソーム / チャネル蛋白 / 細胞内輸送 / ATP依存的 / ランゲンドルク灌流 |
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| Research Abstract |
Prolonged QT interval has been reported to reflect an increased in homogeneity of ventricular repolarization, which is believed to be responsible for the development of arrhythmic event in patients with coronary heart disease and myocardial infarction. On top of that, adenosine triphosphate-sensitive potassium channel (the KィイD2ATPィエD2 channel) appears to be one of the most important effectors of ischemic preconditioning. The KィイD2ATPィエD2 channel complex that reconstitutes IKィイD2ATPィエD2 involves the co-assembly of Kir6 channel subunits with the sulfonylurea receptor, SUR. Cardiac KィイD2ATPィエD2 channel are thought to consist of Kir6.2 + SUR2A. The expression level of membrane receptors should be strictly regulated both at transcriptional and post transrictional level. Recent studies have revealed that the ATP-dependent proteolytic system consisting of ubiquitin and proteasomes is responsible for the degradation of membrane proteins.
This study was designed to elucidate whether Kir6.2-proc
… More
essing may involve the ubiquitin/ proteasome pathway. We introduced Flag-tagged mouse Kir6.2 cDNA into COS7 cell, and the lysate was immunopreciitated by anti-Flag antibody, then immunoblotted by anti-ubiquitin antibody. In transfected cells, ubiquitinated species of flag-Kir6.2 was appeared as higher molecular weight bands. In order to define that ubiquitinated-Kir6.2 will be degraded via proteasome, proteasome inhibitors including MG132, ALLN and lactacystin were applied in pulse-chase experiment of Kir6.2. Proteasome inhibitors significantly blocked the degradation of Kir6.2. Furthermore we co-transfected Kir6.2 + SUR2A into COS7 cell with and without proteasome inhibitor, MG132, and recorded the IKィイD2ATPィエD2 was augmented in the cells with MG132 under nicorandil than in those without it.
These results implies that ubiquitin/proteasome system contributes to the degradation of KィイD2ATPィエD2, which in turn indicate proteasome activity could affect the expression of KィイD2ATPィエD2 in the cardiac cells and modify the QT interval after myocardial infarction and the ischemic preconditioning. Less
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