Law F Y, Steinfeld R, Knauf P A
Am J Physiol. 1983 Jan;244(1):C68-74. doi: 10.1152/ajpcell.1983.244.1.C68.
Human K562 leukemic cells exhibit several erythroid properties, including synthesis and expression of the major red blood cell sialoglycoprotein, glycophorin. This has led us to ask if these cells express a functional anion transport system analogous to that which is associated with the other major erythrocyte glycoprotein, band 3. The chloride-36 exchange flux in K562 cells is less than 0.6% of that which would be expected in mature erythrocytes under similar conditions. Unlike red blood cells, K562 cells do not exhibit a high chloride-sulfate selectivity, and various agents that inhibit red blood cell chloride exchange are all much less effective in K562 cells. On the basis of these flux measurements, K562 cells probably contain less than 600 fully functional red blood cell-like band 3 molecules per cell, in contrast to about a million molecules in the mature red blood cell. The possible-existence of greatly altered band 3 molecules with a reduced turnover rate and/or a reduced affinity for chloride and for various inhibitors is unlikely but cannot be completely excluded. Anion transport was also measured in K562 cells that had been induced to increase hemoglobin synthesis by various chemical agents. Even under these conditions, chloride fluxes indicated no substantial increase in the number of functional anion transport sites or their chloride transport rate.
人K562白血病细胞表现出多种红细胞特性，包括主要红细胞唾液糖蛋白血型糖蛋白的合成和表达。这使我们不禁要问，这些细胞是否表达一种类似于与另一种主要红细胞糖蛋白带3相关的功能性阴离子转运系统。K562细胞中的氯-36交换通量不到在类似条件下成熟红细胞预期通量的0.6%。与红细胞不同，K562细胞不表现出高的氯-硫酸根选择性，并且各种抑制红细胞氯交换的试剂在K562细胞中的效果都要差得多。基于这些通量测量结果，K562细胞每个细胞可能含有不到600个功能完全正常的红细胞样带3分子，相比之下，成熟红细胞中约有100万个分子。带3分子周转率降低和/或对氯及各种抑制剂亲和力降低的极大改变的带3分子虽不太可能存在，但也不能完全排除。还对经各种化学试剂诱导增加血红蛋白合成的K562细胞中的阴离子转运进行了测量。即使在这些条件下，氯通量也表明功能性阴离子转运位点的数量或其氯转运速率没有实质性增加。
