Figure 3.

The E−2′I mutation suppresses the gain-of-function effect of the I9′A mutation on GLIC. Macroscopic-current responses of the E−2′I (A) and E−2′I + I9′A (B) mutants to 5-s pulses of pH 4.5 extracellular solution. The displayed traces are representative recordings obtained in the outside-out configuration at −80 mV. (C) Expression of GLIC mutants on the plasma membrane of HEK-293 cells. The presence of GLIC on the cell surface was detected immunochemically using a HA-tag appended to the C-terminal end of each tested construct. Values of chemiluminescence counts divided by protein concentration were normalized to those obtained for the HA-tagged WT GLIC for each individual experiment (n = 3). The mean and standard error of these normalized values were calculated and plotted for each construct.