Molecular basis for the cation-chloride co-transporter activity

离子在细胞膜上的转运对于所有类型细胞的生存都是必不可少的。这种细胞功能是由多种离子通道和转运体介导的。这些分子机制是许多高血压和糖尿病治疗药物的靶点。阳离子-氯共转运体转运Na+， K+和Cl-，但在跨膜的一次转运循环中没有净电荷。这种活性方式是电中性的，这使得很难详细评估活性、药物相互作用和遗传突变的影响。在这项研究中，我们试图建立一个原核生物CCC同源脂质体的重组系统。然而，尽管该同源物具有适合生化分析的特性，但控制其蛋白表达却十分困难。代替这种方法，我们成功地开发了一种基于细胞的平台，作为分析这种转运蛋白的传统方法。

The ion transport across cell membranes is essential for a survival of all types of cells. This cellular function is mediated by various ion channels and transporters. These molecular machineries are targets for many therapeutic drugs for hypertension and diabetes. Cation-chloride co-transporters transport Na+, K+ and Cl-, but there is no net charge for one transport cycle across membranes. This manner of the activity is electroneutral, and makes it difficult to assess the activity, the drug-interaction and the effect of inherited mutations in detail. In this study, we tried to develop the reconstitution system for a prokaryotic CCC homologue to liposomes. However, although the homologue possesses properties suit for biochemical analyses, it was totally difficult to control its protein expression. Instead of this approach, we succeeded to develop a cell-based platform as the conventional method to analyze this transporter.