Mechanism of iodide/chloride exchange by pendrin
Mechanism of iodide/chloride exchange by pendrin
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DOI：
10.1210/en.2004-0048
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发表时间：
2004-09-01
期刊：
影响因子：
4.8
通讯作者：
Suzuki, K
中科院分区：
文献类型：
--
作者：
Yoshida, A;Hisatome, I;Suzuki, K
我们进行了电生理研究，以调查离子转运pendrin，从而了解Pendred综合征的发病机制。使用pendrin转染的COS-7细胞，我们可以证明pendrin转运碘和氯，测量为电压依赖性内向和外向膜电流。在生理浓度下，培养基中的氯离子[CI-]（o）与细胞质碘离子[CI-]（o）有效交换，表明pendrin对氯离子吸收和碘离子流出很重要。虽然观察到培养基中碘离子[I-]（o）与细胞质氯离子[Cl-]（i）的交换，但需要显著高浓度的碘离子（10 mM）。此外，无论是碘或氯需要在细胞膜的两侧的pendrin的阴离子交换活性，表明碘和氯激活pendrin的交换活性，而它们被运输。本研究进一步支持pendrin负责甲状腺细胞中的碘流出，其中细胞内碘浓度高，并且pendrin在其他组织中的一般功能是通过与其他阴离子交换来转运氯。
We performed an electrophysiological study to investigate ion transport of pendrin and thereby understand the pathogenesis of Pendred syndrome. Using pendrin-transfected COS-7 cells, we could show that pendrin transports both iodide and chloride measured as voltage-dependent inward and outward membrane currents. Chloride in the culture medium, [CI-](o), was efficiently exchanged with cytoplasmic iodide, [CI-](o), under physiological concentrations, indicating that pendrin is important for chloride uptake and iodide efflux. Although exchange of iodide in the medium, [I-](o), with cytoplasmic chloride, [Cl-](i), was observed, a significantly high concentration of iodide (10 mm) was required. In addition, either iodide or chloride was required on both sides of the cell membrane for the anion exchange activity of pendrin, indicating that iodide and chloride activate the exchange activity of pendrin while they are transported. The present study further supports that pendrin is responsible for the iodide efflux in thyroid cells where intracellular iodide concentration is high and that the general function of pendrin in other tissues is to transport chloride through exchange with other anions.