REGULATION OF RENAL-CELL ORGANIC OSMOLYTE TRANSPORT BY TONICITY
REGULATION OF RENAL-CELL ORGANIC OSMOLYTE TRANSPORT BY TONICITY
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DOI：
10.1152/ajpcell.1993.265.6.c1449
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发表时间：
1993-12-01
影响因子：
--
通讯作者：
KWON, HM
中科院分区：
文献类型：
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作者：
HANDLER, JS;KWON, HM
在高渗培养基中培养时，Madin-Darby 犬肾细胞会积累几种非扰动有机渗透剂。肌醇、甜菜碱和牛磺酸随着摄取的增加而积累，第一个与钠的进入有关，后两者与钠和氯的进入有关。由于每个协同转运蛋白最大速度的增加，转运速率增加，张力增加后 24 小时达到峰值活性。每个协同转运蛋白的 cDNA 已被克隆。它们的序列表明肌醇协同转运蛋白属于包括钠偶联葡萄糖转运蛋白 (SGLT1) 的基因家族；甜菜碱和牛磺酸协同转运蛋白属于钠和氯偶联转运蛋白基因家族，负责神经元摄取许多神经递质。 mRNA 丰度分析和核连续分析表明，张力的变化对钠肌醇 (SMIT) 和钠氯化甜菜碱 (BGT1) 协同转运蛋白基因的转录有重大影响。随后两种协同转运蛋白的 mRNA 丰度增加以及协同转运蛋白合成的推测增加可以解释响应张力变化的转运活性的增加。
Madin-Darby canine kidney cells accumulate several nonperturbing organic osmolytes when cultured in a hypertonic medium. Myo-inositol, betaine, and taurine are accumulated secondary to an increase in uptake, the first coupled to sodium entry, the latter two coupled to sodium and chloride entry. The transport rates increase as the result of an increase in maximum velocity for each cotransporter, with peak activity 24 h after the increase in tonicity. The cDNA for each cotransporter has been cloned. Their sequences indicate that the myo-inositol cotransporter belongs to the gene family that includes the sodium-coupled glucose transporter (SGLT1); the betaine and taurine cotransporters belong to the gene family of sodium- and chloride-coupled transporters that are responsible for neuronal uptake of many neurotransmitters. Assays of mRNA abundance and nuclear run-on assays reveal that shifts in tonicity have a major effect on transcription of the genes for the sodium-myo-inositol (SMIT) and sodium-chloride-betaine (BGT1) cotransporters. The ensuing increase in mRNA abundance for the two cotransporters and presumed increase in synthesis of the cotransporter proteins can explain the increase in transport activity in response to changes in tonicity.