Figure 5.

Phosphorylation state of the TRESK/TREK-2 tandem channel regulates the open probability of the tandem channel. Mouse TRESK/TREK-2 channels were expressed in HEK293T cells. Experiments were done on excised inside-out patches. Currents were measured at +60, 0, and −60 mV in symmetrical 140 mm KCl solutions. The current level corresponding to the closed state of the channel is marked with a dash on the left side of the recordings. A, representative recording of a dephosphorylated TRESK/TREK-2 channel. To obtain channels in the dephosphorylated state, HEK293T cells expressing mouse TRESK/TREK-2 were pretreated with 0.5 μm ionomycin (Iono) before patch excision. B, representative recording of a phosphorylated TRESK/TREK-2 channel. To obtain channels in the phosphorylated state, HEK293T cells expressing mouse TRESK/TREK-2 were pretreated overnight with 1 μm cyclosprine A (CsA). C, open probability of dephosphorylated (Iono) and phosphorylated (CsA) TRESK/TREK-2 channels determined at −60 and +60 mV is displayed as a scatter plot. The average values for each group are plotted as a column. The difference between the two groups was statistically significant (Student's t test). D, single-channel conductance of dephosphorylated (Iono) and phosphorylated (CsA) TRESK/TREK-2 channels determined at −60 and +60 mV is displayed as a scatter plot. The average values for each group is plotted as a column. The difference between the two groups was not statistically significant (Student's t test).