Figure 4.

PKC activation inhibits SLC26A6 Cl⁻/HCO₃⁻ exchange activity. (A) HEK293 cells were cotransfected with human SLC26A6 and AT_1a-AngII receptor, cDNAs. At 48 h after transfection, Cl⁻/HCO₃⁻ anion exchange assays were performed before, and 10 min after exposure to AngII (1 μM, gray bar). HEK293 cells were exposed to medium containing Cl⁻ (open bar) or Cl⁻-free medium (black bar), to drive the exchange of Cl⁻ for HCO₃⁻. Initial rates of change of pH_i during the first 100 s were estimated by linear regression (dashed line). (B) Mean values of anion transport activity relative to cells expressing SLC26A6 alone. Cells expressing AT_1a receptors were exposed to AngII (1 μM) either in the absence or presence of the PKC inhibitor, CHE (10 μM). SLC26A6-expressing cells were also exposed to 10 min treatment with PMA, either in the presence or the absence of the PKC inhibitor, CHE (10 μM). Rates were measured during HCO₃⁻ influx (black bars) and HCO₃⁻ efflux (white bars). ^*P<0.05, n=4–5. (C) HEK293 cells were either transfected with AT_1aR cDNA, or cotransfected with SLC26A6 and AT_1aR cDNAs. Samples were analyzed by SDS–PAGE, transferred to PVDF membranes, and probed with either anti-AT_1aR antibody (C) or anti-SLC26A6 antibody (D).