Aronson P S, Kuo S M
Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.
Ann N Y Acad Sci. 1989;574:96-101. doi: 10.1111/j.1749-6632.1989.tb25139.x.
Three distinct anion exchangers are described that directly or indirectly mediate Cl- transport across the luminal membrane of the proximal tubule cell. Studies on the intact proximal tubule indicate that the Cl(-)-formate exchanger is a major mechanism for Cl- transport under physiologic conditions. As just discussed, the physiologic importance of the Cl(-)-oxalate and SO4 = (oxalate)-CO3 = exchangers mediating Cl- transport across the luminal membrane of the proximal tubule cell is currently unknown. These three anion exchangers are part of a larger group of at least eight distinct anion transporters in the proximal tubule that share with erythrocyte Band 3 the properties of stilbene sensitivity and/or the ability to mediate anion exchange. It is tempting to speculate that these proximal tubule anion transporters are members of a family of proteins structurally related to the prototypic anion exchanger, erythrocyte Band 3. If this is true, comparing the structures of these anion transporters with each other and with Band 3 should provide important insight into the molecular basis for differences in substrate and inhibitor specificity within this family of transport proteins.
已描述了三种不同的阴离子交换体，它们直接或间接介导氯离子跨近端小管细胞腔膜的转运。对完整近端小管的研究表明，在生理条件下，氯离子-甲酸根交换体是氯离子转运的主要机制。如前所述，氯离子-草酸根和硫酸根（草酸根）-碳酸根交换体介导氯离子跨近端小管细胞腔膜转运的生理重要性目前尚不清楚。这三种阴离子交换体是近端小管中至少八种不同阴离子转运体的一个更大群体的一部分，它们与红细胞带3共享二苯乙烯敏感性和/或介导阴离子交换的能力。很容易推测这些近端小管阴离子转运体是与原型阴离子交换体红细胞带3结构相关的蛋白质家族的成员。如果这是真的，将这些阴离子转运体彼此之间以及与带3的结构进行比较，应该能为深入了解这个转运蛋白家族中底物和抑制剂特异性差异的分子基础提供重要线索。
