Lindsey A E, Schneider K, Simmons D M, Baron R, Lee B S, Kopito R R
Department of Biological Sciences, Stanford University, CA 94305-5020.
Proc Natl Acad Sci U S A. 1990 Jul;87(14):5278-82. doi: 10.1073/pnas.87.14.5278.
We have isolated rat brain cDNA clones encoding AE2, a homologue of the erythrocyte anion exchanger, band 3 (AE1). Immunocytochemistry and in situ hybridization reveal that, in brain, AE2 expression is restricted to the basolateral membrane of the choroid plexus epithelium. Expression of a full-length mouse AE2 cDNA in COS-7 cells resulted in chloride- and bicarbonate-dependent alterations in intracellular pH, demonstrating that AE2 is a Cl/HCO3 exchanger. Cation replacement studies indicate that AE2-mediated exchange is independent of extracellular sodium. COS-7 cells expressing a mutant rat AE2 cDNA clone that lacks the cytoplasmic NH2-terminal 660 amino acids exhibit identical responses to cation and anion substitution. These results indicate that this domain does not play a significant role in either correct insertion of the transporter into the plasma membrane or anion exchange.
我们分离出了编码AE2的大鼠脑cDNA克隆，AE2是红细胞阴离子交换蛋白带3（AE1）的同源物。免疫细胞化学和原位杂交显示，在脑中，AE2的表达局限于脉络丛上皮细胞的基底外侧膜。在COS-7细胞中表达全长小鼠AE2 cDNA导致细胞内pH值出现依赖于氯离子和碳酸氢根离子的变化，表明AE2是一种Cl/HCO3交换蛋白。阳离子置换研究表明，AE2介导的交换不依赖于细胞外钠离子。表达缺失细胞质NH2末端660个氨基酸的突变大鼠AE2 cDNA克隆的COS-7细胞对阳离子和阴离子置换表现出相同的反应。这些结果表明，该结构域在转运蛋白正确插入质膜或阴离子交换过程中均不发挥重要作用。
