Kopito R R
Department of Biological Sciences, Stanford University, California 94305.
Int Rev Cytol. 1990;123:177-99. doi: 10.1016/s0074-7696(08)60674-9.
The gene family of anion exchangers consists of at least four or five members, of which three have been characterized at the cDNA level. AE1-3 encode polypeptides that share significant homology with the erythrocyte anion exchanger, band 3 (AE1). Expression of cDNAs encoding these genes in heterologous systems confirms that this sequence similarity is reflected in the capacity to mediate reversible Cl/HCO3 exchange. While the NH2-terminal domain of band 3 is known to interact with several cytoplasmic proteins in erythrocytes, the function of the analogous domains of AE2 and AE3 remains unknown. The AE1 gene is expressed coordinately with other erythroid genes during erythropoiesis in both avian and mammalian erythroid progenitor cells. In addition, AE1 is expressed at the basolateral plasma membrane of the acid-secreting intercalated cells of the kidney. AE2 is expressed in a number of epithelial and nonepithelial cells; it may be expressed in the Golgi apparatus of some of these cells. AE3 is expressed in excitable tissues, including neurons and muscle. It is likely that these proteins play a role in regulation of intracellular pH and chloride in their respective tissue. Understanding of the physiological roles of these proteins, both for ion transport and for plasma membrane organization, remains a central issue.
阴离子交换蛋白基因家族至少由四到五个成员组成，其中三个已在cDNA水平得到表征。AE1 - 3编码的多肽与红细胞阴离子交换蛋白带3（AE1）具有显著的同源性。在异源系统中编码这些基因的cDNA的表达证实，这种序列相似性反映在介导可逆性Cl⁻/HCO₃⁻交换的能力上。虽然已知带3的氨基末端结构域与红细胞中的几种细胞质蛋白相互作用，但AE2和AE3类似结构域的功能仍然未知。在鸟类和哺乳动物的红细胞祖细胞的红细胞生成过程中，AE1基因与其他红细胞基因协调表达。此外，AE1在肾泌酸闰细胞的基底外侧质膜上表达。AE2在许多上皮细胞和非上皮细胞中表达；它可能在其中一些细胞的高尔基体中表达。AE3在包括神经元和肌肉在内的可兴奋组织中表达。这些蛋白质可能在各自组织中调节细胞内pH值和氯化物方面发挥作用。了解这些蛋白质在离子运输和质膜组织方面的生理作用仍然是一个核心问题。
