Molecular cloning of the cDNA for an MDCK cell Na(+)- and Cl(-)-dependent taurine transporter that is regulated by hypertonicity.
Molecular cloning of the cDNA for an MDCK cell Na(+)- and Cl(-)-dependent taurine transporter that is regulated by hypertonicity.
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DOI：
10.1073/pnas.89.17.8230
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发表时间：
1992-09
影响因子：
11.1
通讯作者：
S. Uchida;H. Kwon;A. Yamauchi;A. Preston;F. Marumo;J. Handler
中科院分区：
文献类型：
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作者：
S. Uchida;H. Kwon;A. Yamauchi;A. Preston;F. Marumo;J. Handler
摘要高渗肾髓质中的细胞通过积累高浓度的非干扰性小有机溶质（称为渗透剂），使细胞内离子浓度保持在等渗水平，尽管细胞外电解质浓度高得多。牛磺酸已被确定为肾髓质和Madin-Darby犬肾（MDCK）细胞中的非干扰性渗透剂。在高渗培养基中，MDCK细胞中牛磺酸积累增加是Na（+）和Cl（-）依赖性牛磺酸转运蛋白活性增加的结果。我们已经分离了一个编码Na（+）和Cl（-）依赖性牛磺酸转运蛋白的cDNA，其序列对应于一个655个氨基酸的蛋白质，与先前克隆的Na（+）和Cl（-）依赖性转运蛋白具有显著的氨基酸序列相似性，包括MDCK细胞甜菜碱/γ-氨基丁酸转运蛋白和几种脑神经递质转运蛋白。北方杂交表明牛磺酸转运蛋白的mRNA存在于肾皮质和髓质、回肠粘膜、脑、肝和心脏中。在高渗培养基中培养的MDCK细胞中，牛磺酸转运蛋白的mRNA丰度增加，表明通过介质高渗调节转运活性发生在mRNA积累水平。
Abstract Cells in the hypertonic renal medulla maintain their intracellular ion concentration at isotonic levels, despite much higher concentrations of extracellular electrolytes, by accumulating high concentrations of nonperturbing small organic solutes termed osmolytes. Taurine has been identified as a nonperturbing osmolyte in the renal medulla and Madin-Darby canine kidney (MDCK) cells. In hypertonic medium, the increased accumulation of taurine in MDCK cells is the result of increased activity of a Na(+)- and Cl(-)-dependent taurine transporter. We have isolated a cDNA encoding a Na(+)- and Cl(-)-dependent taurine transporter, whose sequence corresponds to a protein of 655 amino acids with significant amino acid sequence similarity to previously cloned Na(+)- and Cl(-)-dependent transporters, including the MDCK cell betaine/gamma-aminobutyric acid transporter and several brain neurotransmitter transporters. Northern hybridization indicates that mRNA for the taurine transporter is present in renal cortex and medulla, ileal mucosa, brain, liver, and heart. The abundance of mRNA for the taurine transporter is increased in MDCK cells cultured in hypertonic medium, suggesting that regulation of transport activity by medium hypertonicity occurs at the level of mRNA accumulation.