| Project/Area Number |
15590747
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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 | National University Corporation Tottori University |
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Principal Investigator |
HISATOME Ichiro Tottori University, Graduate School of Medical Science, Processor, 大学院・医学系研究科, 教授 (60211504)
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| Co-Investigator(Kenkyū-buntansha) |
IGAWA Osamu Tottori University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (80252857)
TANIGUCHI Sinn-ici Tottori university, Faculty of medicine, Assistant Professor, 医学部, 講師 (30304207)
NINOMIYA Haruaki Tottori University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (80212124)
KURATA Yasutaka Kanazawa Medical University, Associate Professor, 医学部, 助教授 (00267725)
MORISAKI Takayuki National Cardiovascular Center, Director, バイオサイエンス部, 研究部長 (30174410)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2004: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2003: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | atrial fibrillation / ion channel / ubiquitin-proteasome / Na^+ channel blockers / SNPs / ユビキチン・プロテアソーム / Na channel 阻害剤 / 蛋白安定化 / Kv1.5 / HSP70 / ユビキチン化 / 細胞内トラフィック / 小胞体品質管理機構 |
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| Research Abstract |
Background : Previously we reported that ion channels responsible for chronic atrial fibrillation have been degraded by ubiquitin-proteasome, which was modification by antiarrhythmic agents. In the current study, we elucidated its underlying mechanism and application to the individualizing therapy for atrial fibrillation.
Methods and Results : Na^+ channel blockers, but not either Ca^<2+> antagonists or K^+ channel blockers, blocked 20S proteasome activity to stabilize the short-lived proteins including p53,IKK2 and Kv1.5 assessed by pulse-chase analysis, immnofluorescence and patch clamp techniques in transfected COS cells. To confirm that p53 stabilization by Na^+ channel blockers was secondary to proteasome inhibition, we examined whether Mdm2 (C438A) could block the drug effects. When co-expressed with Mdm2 (C438A), p53-FLAG was not at all ubiquitinated even when cells were treated with MG132 and this drug failed to increase the p53-FLAG protein level. Likewise, p53-FLAG was not ubiquitinated in cells treated with Na^+ channel blockers, which failed to increase the protein level. Na^+ channel blockers stabilized the short-lived Kir6.2 channel proteins like MG132. There were several SNPs on the lysine residues in the coding region of Kir6.2, suggesting SNPs can affect the extent of channel protein degradation.
Conclusion : Expression of short-lived ion channels have been regulated by ubiquitin-proteasome, which can be modulated by Na^+ channel blockers. Based on the SNPs information, a pharmacological therapy to regulate proteasomal degradation of channel protein can be available for treating the patients with chronic atrial fibrillation.
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