Fig. 6.

CK2 inhibition by TBB or CX4945 reduces the activity of the basolateral Cl⁻/HCO₃ ⁻ exchanger: Calu-3 cells were loaded with BCECF-AM (10 μM; 1 h) and pH_i was determined by fluorescent microscopy. The activity of the basolateral Cl⁻/HCO₃ ⁻ exchanger was assessed by measuring pH_i changes in response to replacement of basolateral Cl⁻ with gluconate. a Shows a representative experiment in which Calu-3 cells were exposed to TBB (10 μM) for 5 min and Cl⁻/HCO₃ ⁻ exchanger activity measured. b and c summarize the effect of TBB treatment and TBB reversibility on the mean change in pH_i caused by basolateral Cl⁻ removal and the rate of reacidification upon Cl⁻ readdition, respectively. *Significant effect of TBB vs. untreated controls (p < 0.05). Data represents mean ± S.E.M., n = 6. d Shows a representative experiment in which Calu-3 cells were exposed to CX4945 (10 μM) for 5 min and Cl⁻/HCO₃ ⁻ exchanger activity measured. e and f summarize the effect of CX4945 treatment and CX4945 reversibility on the mean change in pHi caused by basolateral Cl⁻ removal and the rate of reacidification upon Cl⁻ readdition, respectively. *Significant effect of CX4945 vs. untreated controls (p < 0.05). Data represents mean ± S.E.M., n = 6