Functional identity of a purified proximal tubule anion exchanger protein: mediation of chloride/formate and chloride/bicarbonate exchange.
Functional identity of a purified proximal tubule anion exchanger protein: mediation of chloride/formate and chloride/bicarbonate exchange.
复制标题
纯化的近端小管阴离子交换蛋白的功能特性：介导氯离子/甲酸盐和氯离子/碳酸氢盐交换。
DOI：
10.1038/ki.1996.513
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发表时间：
1996
影响因子：
19.6
通讯作者：
Bizal,GL
中科院分区：
文献类型：
--
作者：
Soleimani,M;Bizal,GL
纯化的近端小管阴离子交换蛋白的功能特性：氯离子/甲酸盐和氯离子/碳酸氢盐交换的介导。基于转运活性和抑制剂敏感性，已在肾近曲小管中鉴定出阴离子交换剂的不同功能模式，包括氯离子/甲酸根、氯离子/草酸根、氯离子/羟基和氯离子/碳酸氢根交换。关于这些过程所涉及的蛋白质的分子结构和特性的信息很少。此前，我们使用二苯乙烯亲和基质和 Pac Q 层析，部分纯化了从兔肾近端小管分离的刷状缘膜（BBM）中具有阴离子交换特性的蛋白质。该蛋白质的分子量为 162 kDa。当重组为脂质体时，含有 162 kDa 蛋白质的级分表现出 Cl-/Cl-交换活性。在当前的实验中，结合使用亲和层析、离子交换层析和尺寸排阻层析，将 162 kDa 蛋白质纯化至均质。该蛋白质对已知的阴离子交换剂抑制剂具有结合亲和力。当在脂质体中重构时，通过 36 Cl-/Cl-交换测定，162 kDa 蛋白质显示出阴离子交换活性。用纯化的 162 kDa 蛋白质重构的脂质体的功能研究表明，该蛋白质介导 Cl-/甲酸盐和 Cl-/HCO 3- 的转运。在 DIDS 和呋塞米（两种已知的肾阴离子交换抑制剂）存在下，重构脂质体中的 Cl-/甲酸盐和 Cl-/HCO 3- 交换活性受到抑制。我们得出结论，肾近曲小管中的 Cl-/甲酸交换和 Cl-/HCO 3- 交换是通过相同的蛋白质介导的。该蛋白与已知的阴离子交换蛋白（AE1、AE2 和 AE3）不同，可能代表该转运蛋白家族的另一种亚型。
Functional identity of a purified proximal tubule anion exchanger protein: Mediation of chloride/formate and chloride/bicarbonate exchange. Based on the transport activities and inhibitor sensitivities, different functional modes of anion exchangers have been identified in the kidney proximal tubule including chloride/formate, chloride/oxalate, chloride/hydroxyl, and chloride/bicarbonate exchange. There is little information on the molecular structure and properties of the protein (s) involved in these processes. Previously, using stilbene affinity matrix and Pac Q chromatography, we partially purified a protein with anion exchange properties in brush border membranes (BBM) isolated from rabbit kidney proximal tubules. This protein has a molecular weight of 162 kDa. When reconstituted into liposomes, the fraction containing the 162 kDa protein demonstrated Cl-/Cl-exchange activity. In the current experiments, the 162 kDa protein was purified to homogeneity using a combination of affinity, ion exchange, and size exclusion chromatography. This protein has binding affinity for known inhibitors of anion exchangers. When reconstituted in liposomes, the 162 kDa protein showed anion exchange activity as assayed by 36 Cl-/Cl-exchange. Functional studies in liposomes reconstituted with the purified 162 kDa protein revealed that this protein mediates the transport of Cl-/formate and Cl−/HCO 3−. The Cl-/formate and Cl−/HCO 3− exchange activities in the reconstituted liposomes were inhibited in the presence of DIDS and furosemide, two known inhibitors of renal anion exchangers. We conclude that Cl-/formate exchange and and Cl−/HCO 3− exchange in kidney proximal tubules are mediated via the same protein. This protein is distinct from the known anion exchanger proteins (AE1, AE2, and AE3) and may represent another isoform from this family of transporters.