ELECTRONEUTRAL AND SLOW-RATE TRANSPORTERS

该子项目是利用NIH/NCRR资助的中心赠款提供的资源的许多研究子项目之一。子项目和研究者（PI）可能从另一个NIH来源获得主要资金，因此可以在其他CRISP条目中表示。所列机构为中心，不一定是研究者所在机构。电中性和慢速率转运蛋白的研究已经落后于产电转运蛋白的研究，由于难以监测转运速率。电压钳用于测量与具有高转运速率的高密度生电转运蛋白的系统中的转运速率成比例的电流。这是用于监测转运动力学的实时测定。然而，电中性转运蛋白根本不产生电流，而慢速率转运蛋白产生的电流是不可检测的，除非转运蛋白密度达到高速率产电转运蛋白所用的1-10千倍。我们已经发现，通过使用细胞外电化学传感器来监测在运输期间建立的梯度，存在用于监测运输的灵敏的实时测定。通过监测浓度梯度中的两个点，我们可以计算与传输速率成比例的分析物的通量。我们以这种方式探索两组不同的转运蛋白，ATP结合盒（ABC）超家族的多药耐药（MDR）转运蛋白和电中性离子转运蛋白，特别是非胃H+/K+转运蛋白。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The study of electroneutral and slow rate transporters has lagged behind the study of electrogenic transporters due to the difficulty in monitoring transport rates. Voltage clamp is used to measure currents that are proportional to transport rates in systems with a high density of electrogenic transporters that have high transport rates. This is a real-time assay for monitoring transport kinetics. Electroneutral transporters, however, do not generate current at all while slow-rate transporters generate current that is not detectable unless transporter density reaches 1-10 thousand times greater than that used with high rate electrogenic transporters. We have found that a sensitive, real-time assay for monitoring transport exists by using extracellular, electrochemical sensors to monitor gradients established during transport. By monitoring two points in the concentration gradient we can calculate flux of the analyte that is proportional to transport rate. We are exploring two separate groups of transporters in this manner, the multidrug resistance (MDR) transporters of the ATP-binding cassette (ABC) superfamily and electroneutral ion transporters, specifically the nongastric H+/K+ transporter.