Sussman I, O'Brien T G
J Cell Physiol. 1985 Jul;124(1):153-9. doi: 10.1002/jcp.1041240124.
A BALB/c 3T3 cell mutant (3T3-E12) was isolated by its ability to survive at a low extracellular K+ concentration (0.14 mM). The growth rate of mutant cells was less dependent on external K+ than parental cells. Analysis of potassium transport revealed that 3T3-E12 cells have a decreased activity of the furosemide-sensitive Na+K+Cl- cotransport system, both in the efflux and influx modes. This is shown to be a result of a decrease in the apparent affinity of the transport system for K+ and Na+, but not Cl-. Upon exposure to the phorbol ester 12-0-tetradecanoyl-phorbol-13-acetate (TPA), BALB/c 3T3 cells exhibited a maximal volume decrease of 20%, while mutant cells shrunk by only 7%, suggesting that regulation of cell volume, at least four exposure to a tumor promoter, is impaired in mutant cells compared to parental 3T3 cells.
通过在低细胞外钾离子浓度（0.14 mM）下存活的能力，分离出了一种BALB/c 3T3细胞突变体（3T3-E12）。突变细胞的生长速率对外部钾离子的依赖性低于亲代细胞。对钾离子转运的分析表明，3T3-E12细胞在流出和流入模式下，速尿敏感的Na+K+Cl-共转运系统的活性均降低。这被证明是转运系统对钾离子和钠离子的表观亲和力降低的结果，而对氯离子的亲和力没有降低。暴露于佛波酯12-0-十四酰佛波醇-13-乙酸酯（TPA）时，BALB/c 3T3细胞的最大体积减少了20%，而突变细胞仅收缩了7%，这表明与亲代3T3细胞相比，突变细胞中细胞体积的调节（至少在暴露于肿瘤启动子的情况下）受损。
