Structure and function of mitochondrial ATP-sensitive K^+ channel.

线粒体 ATP 敏感 K^ 通道的结构和功能。

基本信息

批准号：
11670080
负责人：
GONOI Tohru
金额：
$ 2.43万
依托单位：
Chiba University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11670080/
关键词：
ATP-sensitive K^+ Channel Mitochondria Kir6.1 Kir6.2 SUR1 SUR2 Jurkat cell cAMP-dependent protein kinase ATP感受性K^+チャネル代謝パッチクランプ法 Kir6.2

项目摘要

ATP-sensitive K^+ (K_<ATP>) channels open and close depending on ATP concentration in the cytoplasm, and control excitability of the cells. We have previously shown that K_<ATP> channel of pancreatic β-cell comprises SUR1, a member of ABC protein, and Kir6.2, a member of inward rectifier K channels. In heart and skeletal muscles, and blood vessels, K_<ATP> channels of similar properties comprise SUR2A/B and Kir6.x, regulating muscle contraction during hypoxia or ischemia.Although similar K_<ATP> channel is expressed in mitochondria, and regulating energy metabolism, its constituting molecules are unknown.Using the patch-clamp technique, we recorded ion channel activity from the mitochondrial inner membrane of Jurkat cells. K^+ ion selective channels with conductance of 55 pS were observed, of which activity being suppressed by 2 mM ATP.These properties and burst kinetics are similar to the channel comprising Kir6.1 molecule. In other to study if Kir6.1 molecules are induced during hypo … More xia, A7r5 cells, derived from blood vessel were cultured in medium containing Co^<2+> ions, mimicking hypoxic conditions. Western blotting using anti Kir6.1 antibody revealed that Kir6.1 protein became expressed in 3-4 days after an addition of the ions. However, no activity of channels comprising activity Kir6.1 was observed in the plasma membrane of heart of blood vessel muscles. Following these results, a possibility that Kir6.1 molecule induced in ischemia composes mitochondrial K_<ATP> channel is currently investigated.In other series of experiments effects of protein kinase A mediated phosphorylation of K_<ATP> channels comprising SUR1 and Kir6.2 were studied. We found both subunits are phosphorylated and channel properties are modulated in a different manner.Finally, effects of anti-diabetic reagents, troglitazone, pioglitazone, and KAD-1229, were studied on reconstituted K_<ATP> channels. The studies are helpful in understanding structure-function relationship of K_<ATP> channels in the plasma membrane as well as mitochondria. Less

ATP敏感的K^+（K_ <ATP>）通道取决于细胞质中的ATP浓度，并控制细胞的刺激。我们先前已经表明，胰腺β细胞的K_ <ATP>含量包括ABC蛋白的成员SUR1和内向整流器K通道的成员Kir6.2。在心脏和骨骼肌肉以及血管中，K_ <ATP>类似特性的通道包括SUR2A/B和Kir6.x，调节低氧或缺血期间肌肉收缩的调节。尽管相似的K_ <ATP>通道在线粒体中表现出相似的K_ <ATP>信道，并且在线粒体中表现出了构造的构造，其构造的动态是pictermist的picteriire weeming weement weement potter.sonement weement wee已知，是在pickol.s pote ramp we已知的，仅在于，它是彼此的斑点。线粒体内膜的Jurkat细胞。观察到具有55 ps的电导率的K^+离子选择性通道，其中活性被2 mM ATP抑制。这些特性和爆发动力学与完成Kir6.1分子的通道相似。在其他过程中，在低于血管中诱导的kir6.1分子是否是在含有血管中衍生的更多的Xia，A7R5细胞的，在含有Co^<2+>离子的培养基中培养，模仿低氧条件。使用抗Kir6.1抗体的蛋白质印迹显示，添加离子后的3-4天，Kir6.1蛋白在3-4天内表达。但是，在血管肌肉心脏的质膜中未观察到包括活性Kir6.1的通道活性。遵循这些结果，目前研究了缺血中诱导的线粒体K_ <ATP>通道的Kir6.1分子的可能性。我们发现两个亚基都是磷酸化的，并以不同的方式调节了通道性能。在重新建立的K_ <ATP>通道上研究了抗糖尿病试剂，troglitazone，pioglitazone和Kad-1229的作用。这些研究有助于理解质膜和线粒体中K_ <ATP>通道的结构功能关系。较少的