ELECTRONEUTRAL AND SLOW-RATE TRANSPORTERS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。由于难以监测传输速率，电中性和慢速率传输体的研究落后于电致传输体的研究。电压钳用于测量在具有高输运率的高密度致电转运体的系统中与输运率成正比的电流。这是一种实时检测运输动力学的方法。然而，电中性转运体根本不产生电流，而慢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电致转运体密度的1-1万倍。我们发现，通过使用细胞外电化学传感器来监测运输过程中建立的梯度，存在一种敏感、实时的监测运输的方法。通过监测浓度梯度中的两点，我们可以计算出与输运率成正比的分析物通量。我们正在以这种方式探索两组不同的转运体，atp结合盒（ABC）超家族的多药耐药（MDR）转运体和电中性离子转运体，特别是非胃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.