Figure 3.

Inhibition of SLC26A6 Cl⁻/HCO₃⁻ exchange activity by manipulation of CA. (A) HEK293 cells, individually transfected with SLC26A6, SLC26A6-ΔCAB, or cotransfected with SLC26A6 and V143Y CAII cDNAs, were loaded with BCECF-AM. Cells were perfused alternately with Cl⁻-containing (open bar) and Cl⁻-free (black bar) Ringer's. In some experiments, cells were incubated with 1 mM DIDS between the first and second cycles of buffer switching. SLC26A6-transfected HEK293 cells were switched from Cl⁻-containing to Cl⁻-free Ringer's buffer and the process was repeated, but in the presence of the membrane-permeant CA inhibitor 150 μM ACTZ (gray bar). (B) Cl⁻/HCO₃⁻ exchange activity, relative to WT SLC26A6, for SLC26A6 or SLC26A6-ΔCAB expressed alone or coexpressed with functionally inactive V143Y CAII (n=4–6). ^*P<0.05. Rates were measured during HCO₃⁻ influx (black bars) and HCO₃⁻ efflux (white bars).