Elucidation of the mechanisms underlying the regulation of ATP-sensitive K^+ channels by sulfonylureas

阐明磺酰脲类药物调节 ATP 敏感 K^ 通道的机制

• 批准号: 09671025
• 负责人: INAGAKI Nobuya
• 金额: $ 2.3万
• 依托单位: Akita University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09671025/
• 关键词: sulfonylurea; ATP-sensitive K^* channel; inward rectifier K^* channel; knockout mouse; pancreatic beta-cell; ABC protein; cardiac myocyte; スルホニル尿素; ATP感受性Kチャネル; ATP; イオンチャネル; インスリン

ATP-sensitive K^+(K_<ATP>) channels are key molecules which link the cell's metabolic status to its membrane potential. In pancreatic beta-cells, KK_<ATP> channel is not only a glucose sensor m insulin secretion but also a target for the insulin secretagogue, the sulfonylurea, widely used as oral hypoglycemic agents in the treatment of diabetes mellitus. In cardiac myocytes and neurons, K_<ATP> channels are supposed to be involved in cytoprotection in ischemia, We have shown that beta-cell K_<ATP> channel is a complex of the sulfonylurea receptor SURI and a newly cloned inward rectifier K_<ATP> channel member Kir6.2, and that cardiac myocyte K_<ATP> channel is a complex of the newly cloned sulfonylurea receptor SUR2 and the Kir6.2. Our purpose in this study is to clarify the molecular mechanisms underlying the regulation of K^+ channels.Sensitivities of the [3-cell (SUR1/Kir6.2) and cardiac (SUR2/Kir6.2) K_<ATP> channels to the sulfonylurea glibenclamide and the K_<ATP> channel opener … More diazoxide are different, and are determined by distinct SUR subunits. To determine the domains that confer glibenclamide and diazoxide sensitivities, we prepared a series of chimeras between SUR1 and SUR2, and studied the properties of the chimeric K_<ATP> channels. All chimeric SURs could generate currents when expressed in COS 1 cells with Kir6.2. Next, we have examined the effects of the glibenclamide and diazoxide on the chimeric currents measured as ^<86>Rb^+ efflux, and narrowed the region that confer the sensitivities to these reagents. Furthermore, we have constructed various chimeras between SUR1 and SUR2, and have almost determined the glibenclamide-responsive region by measuring the binding activities of @SH-labeled glibenclamide for the chimeras expressed in COS 1 cells (manuscript in 3@E1preparation).In addition, we have investigated the effects of G-protein on the reconstituted K_<ATP> channels. We have shown that G-protein alpha subunit directly regulates the K_<ATP> channel activity, and that the regulation is different between [3-cell (SUR1/Kir6.2) and cardiac (SUR2/Kir6.2) K_<ATP> channels, suggesting that the difference is determined by distinct SUR subunits. Less

ATP敏感性K^+（K_<ATP>）通道是连接细胞代谢状态与膜电位的关键分子。在胰岛β细胞中，KK_2<ATP>通道不仅是胰岛素分泌的葡萄糖传感器，而且是胰岛素促分泌剂磺酰脲类药物的作用靶点，磺酰脲类药物广泛用作口服降糖药治疗糖尿病。在心肌细胞和神经元中，K_<ATP>通道被认为参与了缺血时的细胞保护作用。我们发现β细胞K_<ATP>通道是磺酰脲类受体SURI和新近克隆的内向整流性K_通道成员Kir6.2的复合体<ATP>，心肌细胞K_<ATP>通道是新近克隆的磺酰脲类受体SUR 2和Kir6.2的复合体。本研究的目的是阐明钾通道调节的分子机制。[3]-细胞（SUR 1/Kir6.2）和心脏（SUR 2/Kir6.2）钾<ATP>通道对磺脲类药物格列本脲和钾<ATP>通道开放剂的敏感性 ...更多信息 二氮嗪是不同的，并由不同的SUR亚基决定。为了确定赋予格列本脲和二氮嗪敏感性的结构域，我们制备了一系列SUR 1和SUR 2之间的嵌合体，并研究了嵌合体K_通道的特性<ATP>。所有嵌合的SURs在含有Kir6.2的COS-1细胞中表达后均能产生电流。接下来，我们检测了格列本脲和二氮嗪对以^ Rb^+外排测定的嵌合电流的影响<86>，并缩小了对这些试剂敏感的区域。此外，我们还构建了SUR 1和SUR 2之间的嵌合体，并通过测定在COS 1细胞中表达的嵌合体与@ SH标记的格列本脲的结合活性，基本确定了格列本脲的反应区域（手稿在3@E1制备中），此外，我们还研究了G蛋白对重构的K通道的影响<ATP>。结果表明，G蛋白α亚基直接调节K<ATP>通道活性，且对[3-细胞]（SUR 1/Kir6.2）和心脏（SUR 2/Kir6.2）K通道的调节作用不同<ATP>，提示这种差异是由不同的SUR亚基决定的。少

项目成果

Inagaki, N.: "Diabetes mellitau and KATP channels" Diagnosis and Treatment. 86. 2085-2090 (1998)

Inagaki, N.：“糖尿病和 KATP 通道”诊断和治疗。

稲垣暢也: "糖尿病とK_<ATP2>チャネル." 診断と治療. 86. 2085-2090 (1998)

Nobuya Inagaki：“糖尿病和 K_<ATP2> 诊断和治疗”。86。2085-2090 (1998)

Miki,T., Inagaki,N., et al.: "Abnormalities of pancreatic islets by targetted expression of dominant-negative K_<ATP> channel." Proc. Natl, Acad. Aci, USA.94. 11969-11973 (1997)

Miki,T.、Inagaki,N. 等人：“显性失活 K_<ATP> 通道的靶向表达导致胰岛异常。”

稲垣暢也: "ATP感受性K^+チャネル" 医学のあゆみ. 188. 309-313 (1999)

Nobuya Inagaki：“ATP 敏感 K^+ 通道”医学史 188. 309-313 (1999)。

Inagaki, N.: "Molecular structure and function of KATP channels." Kidney and Dialysis. 45. 651-656 (1998)

Inagaki, N.：“KATP 通道的分子结构和功能。”