Functional incorporation of the human erythrocyte chloride exchange system into plasma membranes of Friend erythroleukemic cells by Sendai virus-induced cell fusion

Human erythrocytes (RBC) were shown to exchange Cl^- by an exceptionally fast mechanism (t _{1 2} of ³⁶Cl^- equilibration at 1 °C is approx. 20 sec) which is demonstrably susceptible to specific inhibitors of anion exchange such as 4,4′-dinitrostilbene-2,2′-disulfonic acid (DNDS) and 4,4′-diisothyocyano-2,2′stilbene disulfonic acid (DIDS). Friend erythroleukemic cells (FELC) on the other hand, display both markedly slower Cl^- exchange rates (t _{1 2} of ³⁶Cl^- equilibration at 1 °C is approx. 60 min) and substantially lower susceptibilities to either DNDS or DIDS than RBC. After fusion between RBC and FELC, Cl^- exchange across FELC-RBC plasma membranes was noticeably enhanced compared with FELC. This enhancement was specificially abolished either by the addition of DNDS or by fusing FELC with DIDS-treated RBC.