ROMK CHANNEL FUNCTION AND REGULATION IN KIDNEY

我们的研究项目将集中于探索有关肾脏钾(K)通道(ROMK)调节的尚未解决的问题。肾脏在钾的动态平衡中起主要作用，它通过平衡主肾小管细胞的钾分泌和远端肾单位嵌插细胞对钾的重吸收来实现。在Na-K-ATPase通过基侧膜主动摄取钾之后，通过低电导钾通道扩散通过主细胞的顶膜。这些通道已经被克隆，我们建议探索它们的调控机制。我们将追求两个主要目标。首先，我们建议探索依赖核苷酸的通道门控由激酶、pH和磷脂调节，以及通道亚基的化学计量比。第二，由于最近的研究已经确定了Bartter综合征中ROMK的缺失，这是一种肾脏钠和钾损耗的情况，我们计划在ROMK敲门-但模型中研究心尖钾通道丢失的影响。我们还将研究钾分泌的替代运输机制。膜片钳和全细胞电流测量将在天然小管和卵母细胞表达系统中进行，并将在ROMK基因敲除小鼠中进行小管灌流研究。

Our research project will focus on the exploration of unresolved problems concerning the regulation of renal potassium (K+) channels (ROMK). The kidney plays a major role in potassium homeostasis by a balance between potassium secretion in principal tubule cells and potassium reabsorption in intercalated cells of the distal nephron. Following active uptake of potassium across the basolateral membrane by Na-K+ ATPase, diffusion across the apical membrane of principal cells occurs via low-conductance potassium channels. These channels have been cloned and we propose to explore the mechanism of their regulation. Two major goals will be pursued. First, we propose to explore the regulation of nucleotidedependent channel gating by kinases, pH and phospolipids, and the stoichiometry of channel subunits. Second, because recent studies have identified ROMK deletions in Bartter's syndrome, a condition of renal sodium (Na) and K+ wasting, we plan to study the effects of loss of apical potassium channels in a ROMK knock-but model. We will also examine alternative transport mechanisms of K+ secretion. Patch-clamp and whole-cell current measurements will be carried out in native tubules and in an oocyte expression system, and tubule perfusion studies in ROMK knock-out mice.