Fig. 3.

Chronic AF in human subjects is not associated with changes in total TASK-1 protein levels or Thr³⁸³ phosphorylation. Crude membrane fractions of left atrial tissue taken from human valve repair patients in NSR or with AF were resolved by SDS-PAGE and blotted to nitrocellulose. Protein was visualized using an antibody to total TASK-1 or to phosphorylated Thr³⁸³ (pT383) TASK-1, and band densities were quantified. TASK-1 levels were measured either two or three times for each subject, and the average was plotted in a scatterplot (○). Means ± SE for all subjects are shown (●). A: representative Western blots of tissue from subjects in NSR or with AF immunoblotted for total TASK-1 (top) and pT383 TASK-1 (bottom). B: there was no difference in average total TASK-1 band intensity of tissue from all subjects in NSR (n = 21) versus all subjects with AF (n = 19). C: there was also no difference in the ratio of pT383 to total TASK-1 band intensity in tissue from all subjects in NSR versus all subjects in AF. D and E: in an age-matched subset of subjects, there was likewise no difference between subjects in NSR versus subjects with AF in total TASK-1 band intensity (D; n = 13 in the NSR group and n = 10 in the AF group) or in the ratio of pT383 to total TASK-1 band intensity (E).