ELECTRONEUTRAL AND SLOW-RATE TRANSPORTERS

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。由于监测转运速率的困难，对电子中和和慢速转运体的研究一直落后于产生电的转运体的研究。电压钳用于测量与传输速率成正比的电流，这些电流与传输速率高的生电传输器密度高的系统中的电流成比例。这是一种实时监测转运动力学的方法。然而，电子中和转运体根本不产生电流，而低速转运体产生的电流是无法检测到的，除非转运体密度达到高速率产电转运体的1-1万倍。我们发现，通过使用细胞外的电化学传感器来监测运输过程中建立的梯度，存在一种灵敏的、实时的监测运输的方法。通过监测浓度梯度中的两点，我们可以计算出与传输速率成正比的分析物的通量。我们正在以这种方式探索两组不同的转运体，即ATP结合盒(ABC)超家族的多药耐药(MDR)转运体和电子中和离子转运体，特别是非胃肠道的H+/K+转运体。

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.