Mechanisms and regulation of renal urinary concentration

肾尿浓度的机制和调节

基本信息

批准号：
09307022
负责人：
TERADA Yoshio
金额：
$ 25.28万
依托单位：
Tokyo Medical and Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

1) Cloning of water channels (AQPs)We cloned the following AQPs ; AQP7 from rat testis that has permeability to glycerol and urea in addition to water, AQP8 from rat testis that is water-selective, AQP9 from human leukocyte that has permeability to urea in addition to water, and AQP9L, a homologue of AQP9, from rat liver.2) Determination of AQP structurea. We identified mercury-sensitive cystein in human AQP3 and showed evidence suggesting that water, glycerol, and urea share a common pore.b. AQP family is divided into two groups ; MIP group that is water-selective and glpF group that is permeable to small molecules. Only the latter group possesses two portions which are composed of about 15 amino acid. We examined the significance of these portions and found the portions are not associated with channel selectivity.c. AQP2 and MIP are highly homologous (58% amino acid homology), whereas the water permeability of AQP2 is much higher than that of MIP. We constructed chimera proteins of AQP2 and MIP and determined several amino acids in transmembrane helix5 is responsible for the high water permeability of AQP.3. Intracellular mechanisms and signal transduction related to urinary concentrationa. A short or a long time exposure to high osmolality decreased the activity of Na-K-ATPase in rat inner medullary collecting duct cells. We found that the mechanism of Na-K-ATPase inhibition was different in the short and long time exposure.b. We investigated signal transduction pathways in LLC-PK1 and mesangial cells and obtained several new findings.4. Pathogenesis of nephrogenic diabetes insipidus (NDI)a. We characterized T125M and G175R, AOP2 mutants found in autosomal recessive NDI, and found the decrease of the water channel function of these mutants.b. We characterized 809del 7, and AQP2 mutant found in autosomal dominant NDI, and found that this mutation causes the inhibition of transcription or the defect of protein trafficking.

1）水通道的克隆（AQP）我们克隆了以下AQP；除了水外，还对甘油和尿素具有渗透性的AQP7，来自大鼠睾丸的AQP8，具有水选择性的AQP8，来自人类白细胞的AQP9除了对水的渗透性以及AQP9L，AQP9L，AQP9L，AQP9L，AQP9的AQP9，一种AQP9的同源物。我们在人AQP3中确定了对汞敏感的半胱氨酸，并显示了证据表明水，甘油和尿素共有一个共同的毛孔。 AQP家族分为两组；水选择性和GLPF组的MIP组，可渗透到小分子。只有后一组具有由约15个氨基酸组成的两部分。我们检查了这些部分的重要性，发现这些部分与通道选择性无关。 AQP2和MIP高度同源（58％氨基酸同源性），而AQP2的水渗透性远高于MIP。我们构建了AQP2和MIP的嵌合蛋白，并确定了跨膜螺旋中的几个氨基酸，负责AQP.3的高水渗透性。细胞内机制和与尿液浓度有关的信号转导。短期或长时间暴露于高渗透压会降低Na-k-ATPase在大鼠内髓质收集管细胞中的活性。我们发现Na-K-ATPase抑制的机制在短时间内暴露b。我们研究了LLC-PK1和中键细胞中的信号转导途径，并获得了几个新发现。4。肾脏基糖尿病（NDI）的发病机理a。我们表征了T125M和G175R，这是在常染色体隐性NDI中发现的AOP2突变体，并发现这些突变体的水信道功能的降低。我们表征了809del 7和在常染色体显性NDI中发现的AQP2突变体，发现该突变会导致转录或蛋白质运输的缺陷。