Functional expression of the rat anion exchanger AE2 in insect cells by a recombinant baculovirus

We used baculovirus to transiently express a rat anion exchanger (AE2) in Spodoptera frugiperda (Sf9) insect cells. No detectable Cl(-)-HCO3- exchange activity was observed in wild type or sham-infected Sf9 cells, monitored using 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein, a pH-sensitive fluorescent dye. Functional expression of anion exchange activity in the AE2 recombinant baculovirus-infected cells was observed within the first day after infection and sustained over the next 3 days. The expressed AE2 anion exchange activity was Na+ independent and could be reversibly and irreversibly inhibited by the specific anion exchange inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS). The reversible inhibition was sensitive to the concentration of DIDS, with a half inhibition of 4 microM. These results indicate that the rat AE2 protein produced in the recombinant baculovirus-infected insect cells is inserted into the plasma membrane in a biologically active form that appears suitable for functional studies of AE2.