Molecular composition of mitochondrial ATP-sensitive potassium channels probed by viral Kir gene transfer.
Molecular composition of mitochondrial ATP-sensitive potassium channels probed by viral Kir gene transfer.
复制标题
DOI：
10.1006/jmcc.2000.1226
复制
发表时间：
2000-11
影响因子：
5
通讯作者：
J. Seharaseyon;A. Ohler;N. Sasaki;H. Fraser;Toshiaki Sato;D. Johns;Brian O’ Rourke;E. Marbán
中科院分区：
文献类型：
--
作者：
J. Seharaseyon;A. Ohler;N. Sasaki;H. Fraser;Toshiaki Sato;D. Johns;Brian O’ Rourke;E. Marbán
心脏细胞在肌膜和线粒体内膜中都含有ATP敏感性钾（KATP）通道。肌膜通道被认为是磺酰脲受体（SUR）和钾内向整流（Kir）基因产物的异源多聚体复合物，但线粒体KATP（mitoKATP）通道的分子身份仍不清楚。为了探测KATP通道的分子组成，我们使用腺病毒基因转移来表达野生型（WT）和显性阴性（AFA）构建的Kir6.1和6.2在兔心室肌细胞。Kir6.1或6.2构建体均不影响线粒体KATP通道活性，这与基于亚细胞抗体定位的Kir6.1形成线粒体KATP通道的一部分的提议相矛盾。如前所述，显性负性Kir6.2基因转移抑制了肌膜KATP电流，而Kir6.1构建体对肌膜活性没有影响。用抗Kir6.1抗体的免疫组织化学显示该蛋白在心脏中表达，但与线粒体没有明显的共定位。因此，现有的证据表明Kir6.1和6.2都在心室肌细胞中表达，但都没有在mitoKATP通道中发挥明显的功能作用。
Heart cells contain ATP-sensitive potassium (KATP) channels in both the sarcolemma and the inner mitochondrial membrane. The sarcolemmal channels are believed to be heteromultimeric complexes of sulfonylurea receptors (SUR) and potassium inward rectifier (Kir) gene products, but the molecular identity of mitochondrial KATP (mitoKATP) channels remains unclear. To probe the molecular composition of KATP channels, we used adenoviral gene transfer to express wild-type (WT) and dominant-negative (AFA) constructs of Kir6.1 and 6.2 in rabbit ventricular myocytes. None of the Kir6.1 or 6.2 constructs affected mitoKATPchannel activity as assayed by confocal imaging of flavoprotein fluorescence, contradicting the proposal, based on subcellular antibody localization, that Kir6.1 forms part of mitoKATP channels. As previously reported, dominant-negative Kir6.2 gene transfer suppressed sarcolemmal KATP current, while Kir6.1 constructs had no effect on sarcolemmal activity. Immunohistochemistry with an anti-Kir6.1 antibody revealed expression of this protein in heart but no apparent co-localization with mitochondria. Thus, the available evidence indicates that both Kir6.1 and 6.2 are expressed in ventricular myocytes, but neither plays a discernible functional role in the mitoKATP channel.