ROMK CHANNEL FUNCTION AND REGULATION IN KIDNEY

我们的研究项目将重点探索肾钾（K+）通道（ROMK）调控的尚未解决的问题。肾脏通过平衡主小管细胞的钾分泌和远端肾元插层细胞的钾重吸收，在钾稳态中起主要作用。Na-K+ atp酶通过基底外侧膜主动摄取钾后，通过低导钾通道向主细胞顶膜扩散。这些通道已经被克隆，我们建议探索它们的调节机制。将追求两个主要目标。首先，我们提出探索激酶、pH值和磷脂对核苷酸依赖性通道门控的调节，以及通道亚基的化学计量学。其次，由于最近的研究已经发现了Bartter综合征（一种肾脏钠（Na）和钾+消耗的情况）中的ROMK缺失，我们计划在ROMK敲除模型中研究根尖钾通道丢失的影响。我们还将研究K+分泌的其他运输机制。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，并在ROMK敲除小鼠中进行小管灌注研究。

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.