The ROMK potassium channel is present in mammalian urinary tract epithelia and muscle.
The ROMK potassium channel is present in mammalian urinary tract epithelia and muscle.
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ROMK 钾通道存在于哺乳动物尿道上皮和肌肉中。
DOI：
10.1152/ajprenal.00022.2008
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Wade,JamesB
中科院分区：
文献类型：
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作者：
Spector,DavidA;Yang,Qing;Klopouh,Leonid;Deng,Jie;Weinman,EdwardJ;Steplock,DeborahA;Biswas,Rajatsubhra;Brazie,MarcF;Liu,Jie;Wade,JamesB
越来越多的证据表明，哺乳动物泌尿道上皮细胞利用膜通道和转运蛋白将溶质转运穿过其顶膜（管腔膜）和基底膜，以改变细胞和尿液中的溶质浓度。本研究探讨了ROMK（Kir1.1）钾通道在大鼠和犬输尿管和膀胱组织中的表达、定位和调节。大鼠和犬的整个输尿管、整个膀胱、膀胱上皮细胞和膀胱平滑肌组织匀浆的免疫印迹鉴定出所有组织中ROMK的45- 50-kDa特征条带。RT-PCR在两种动物的这些相同组织中鉴定出ROMK mRNA。免疫细胞化学定位的ROMK蛋白强烈表达在大伞细胞内衬膀胱腔的顶膜，并在较小程度上在上皮细胞和平滑肌细胞的细胞质中的大鼠膀胱。ROMK蛋白和mRNA也发现在心脏，横纹肌，平滑肌在不同的器官。在高钾或低钾饮食的大鼠组之间，在膀胱匀浆（全膀胱、上皮细胞或肌肉细胞）或输尿管匀浆中ROMK丰度的免疫印迹表达没有差异。虽然ROMK在尿路上皮和平滑肌中的功能作用尚不清楚，但ROMK可能参与调节上皮和平滑肌细胞体积和渗透压，参与钾从尿中泄漏或扩散穿过上皮细胞顶端膜或紧密连接的耗散，以及参与钾穿过尿路上皮的净或双向转运。
There is increasing evidence that mammalian urinary tract epithelial cells utilize membrane channels and transporters to transport solutes across their apical (luminal) and basalateral membranes to modify solute concentrations in both cell and urine. This study investigates the expression, localization, and regulation of the ROMK (Kir1.1) potassium channels in rat and dog ureter and bladder tissues. Immunoblots of homogenates of whole ureter, whole bladder, bladder epithelial cells, and bladder smooth muscle tissues in both rat and dog identified ∼45- to 50-kDa bands characteristic of ROMK in all tissues. RT-PCR identified ROMK mRNA in these same tissues in both animal species. ROMK protein localized by immunocytochemistry was strongly expressed in the apical membranes of the large umbrella cells lining the bladder lumen and to a lesser extent in the cytoplasm of epithelial cells and smooth muscle cells in the rat bladder. ROMK protein and mRNA were also discovered in cardiac, striated, and smooth muscle in diverse organs. There was no difference in immunoblot expression of ROMK abundance in bladder homogenates (whole bladder, epithelial cell, or muscle cell) or ureteral homogenates between groups of rats fed high- or low-potassium diets. Although the functional role of ROMK in urinary tract epithelia and smooth muscle is unknown, ROMK may participate in the regulation of epithelial and smooth muscle cell volume and osmolality, in the dissipation of potassium leaked or diffused from urine across the epithelial cell apical membranes or tight junctions, and in net or bidirectional potassium transport across urinary tract epithelia.