Cloning and functional characterization of inwardly rectifying K^+ channels expressed in pancreatic beta-cells

胰腺β细胞中表达的内向整流K^通道的克隆和功能表征

• 批准号: 07671107
• 负责人: INAGAKI Nobuya
• 金额: $ 1.6万
• 依托单位: Chiba University School of Medicine
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07671107/
• 关键词: insulin; K^+ channel; sulfonylurea; ATP

In pancreatic beta-cells, ATP-sensitive potassium channels (K_<ATP> channels) are crucial for the regulation of glucoseinduced insulin secretion and are the target for the sulfonylureas, oral hypoglycemic agents widely used in the treatment of non-insulin-dependent diabetes mellitus (NIDDM), but the molecular basis of the K_<ATP> channels was unknown. Recently, a high affinity receptor for sulfonylureas (SUR1), a member of the ATP-binding cassette (ABC) superfamily, has been isolated, but it did not elicit K_<ATP> channel currents. We have cloned a member of the inward rectifier K^+ channel family, uK_<ATP>-1 (Kir6.1), which is expressed in various tissues including pancreatic islets, but not in clonal beta-cell lines. Subsequently, we also have cloned BIR (Kir6.2), which belongs to the same subfamily as Kir6.1 and is expressed predominantly in pancreatic islets and clonal beta-cell lines. We have shown that the properties of the K_<ATP> channel reconstituted from SUR1 and Kir6.2 are those described for native pancreatic beta-cells, demonstrating that the pancreatic beta-cell K_<ATP> channel is a complex composed of Kir6.2 and SUR1. We also have isolated a novel sulfonylurea receptor (SUR2) which shares 68% amino acisd identity with SUR1. SUR2 mRNA is abundant in heart and skeletal muscle. Coexpression of SUR2 and Kir6.2 in COS1 cells reconstitutes K_<ATP> channels found in native cardiac and skeletal muscle, indicating that the pharmacological properties of K_<ATP> channels are determined by a family of sulfonylurea receptor subunits. We also have determined the structure and chromosomal localization of human Kir6.2 gene, and have shown that human SUR1 and Kir6.2 genes are clustered at chromosome 11p15.1. We have found several polymorphysms in the Kir6.2 gene and microsatellite DNA polymorphysms close to the Kir6.2 gene, and have shown that genetic variation in the Kir6.2 gene does not play a major role in susceptibility to NIDDM in Japanese and Caucasian.

在胰腺β细胞中，ATP敏感性钾通道（K_<ATP>channels）对于调节葡萄糖诱导的胰岛素分泌至关重要，并且是广泛用于治疗非胰岛素依赖性糖尿病（NIDDM）的口服降糖药磺脲类药物的靶点，但K_ channels的分子基础<ATP>尚不清楚。磺酰脲类药物受体（SUR 1）是ATP结合盒（ABC）超家族的一员，近年来被分离出来，但它不能引起钾<ATP>通道电流。我们克隆了内向整流K^+通道家族的一个成员uK_<ATP>-1（Kir6.1），它在包括胰岛在内的各种组织中表达，但在克隆β细胞系中不表达。随后，我们还克隆了BIR（Kir6.2），其与Kir6.1属于相同的亚家族，并且主要在胰岛和克隆β细胞系中表达。我们已经证明，<ATP>由SUR 1和Kir6.2重建的K_通道的性质与天然胰腺β细胞的性质相同，表明胰腺β细胞K_<ATP>通道是由Kir6.2和SUR 1组成的复合物。我们还分离了一个新的磺酰脲受体（SUR 2），它与SUR 1有68%的氨基酸同源性。SUR 2 mRNA在心脏和骨骼肌中含量丰富。SUR 2和Kir6.2在COS 1细胞中的共表达重建了<ATP>天然心肌和骨骼肌中的K_通道，表明K_通道的药理学特性<ATP>是由磺酰脲类受体亚基家族决定的。我们还确定了人Kir6.2基因的结构和染色体定位，并已表明，人SUR 1和Kir6.2基因聚集在染色体11p15.1。我们发现Kir6.2基因和靠近Kir6.2基因的微卫星DNA多态性存在几种多态性，并表明Kir6.2基因的遗传变异在日本人和高加索人对NIDDM的易感性中不起主要作用。

项目成果

Inagaki,N.et al.: "cDNA sequence,gene structure,and chromosomal localization of the human ATP-sensitive potassium channel,uKATP-1,Gene (KCNJ8)." Genomics. 30. 102-104 (1995)

Inagaki,N.et al.：“人类 ATP 敏感钾通道 uKATP-1 基因 (KCNJ8) 的 cDNA 序列、基因结构和染色体定位。”

Ihara, Y.et al.: "Molecular diversity and functional characterization of voltage-dependent calcium channels (CACN4) expressed in pancreatic beta-cells." Mol.Endocrinol.9. 121-130 (1995)

Ihara, Y. 等人：“胰腺 β 细胞中表达的电压依赖性钙通道 (CACN4) 的分子多样性和功能特征。”

水田雅也 他: "分子糖尿病学の進歩-基礎から臨床まで-1995" 金原出版, 6 (1995)

Masaya Mizuta 等人：“分子糖尿病的进展 - 从基础知识到临床实践 - 1995” Kanehara Publishing，6 (1995)

Ihara,Y.et al.: "Molecular diversity and functional characterization of voltage-dependent calcium channels (CACN4) expressed in pancreatic β-cells." Mol. Endocrinol.9. 121-130 (1995)

Ihara, Y. 等人：“胰腺 β 细胞中表达的电压依赖性钙通道 (CACN4) 的分子多样性和功能特征。”121-130 (1995)。

Wang,C-Z.et al.: "Cloning and pharmacological characterization of a fourth P2X receptor subtype widely expressed in brain and peripheral tissues including various endocrine tissues." Biochem. Biophys. Res. Commun.220. 196-202 (1996)

Wang,C-Z.等人：“第四种 P2X 受体亚型的克隆和药理学特征，该亚型广泛表达于大脑和外周组织，包括各种内分泌组织。”