Figure 7.
CBGA inhibitory potency is decreased by increasing serum concentrations. Serum-dependent effects of CBGA on ICRAC and NFAT activity in the presence of 0%, 1%, and 10% FBS. (A) Time course of CRAC currents recorded in Jurkat T cell in whole-cell patch-clamp experiments. Bath solution was supplemented with 0%, 1%, or 10% FBS (0% serum data is the same as in Figure 4A). To elicit the active calcium depletion from the ER, 50 µm IP3 in the recording pipette was utilized. The resulting CRAC currents were allowed to reach maximal activation prior to extracellular application of CBGA at various concentrations. Current amplitudes were measured at −120 mV for each voltage ramp and were normalized to the control at 120 s. n represents the number of cells patched for each condition. (B) Concentration–response effects of CBGA on NFAT activity in the presence of 0%, 1%, and 10% FBS. A 10- and 12-point concentration-response curves, ranging from 100 n m to 100 µm and 100 n m to 300 µm, respectively, were established. The 12-point d/r was used for 10% FBS condition due to the weak activity of CBGA in the ten-point concentration range under this condition. Values are average ± SEM of 12–15 replicates, normalized to the control (cells treated with PMA + Ionomycin only).