Fig. 2

A small-molecule screen in C. elegans identifies a novel hERG trafficking inhibitor. a Schematic illumination of the screening assay. b Molecular formula of alphitolic acid (ALA, upper) and microscopic images of acs-20;hERG^{chimera/A536W} transgenic worms in the presence of 20 µM ALA in cultivating plates (lower). White arrows indicate eggs. c Representative whole-cell currents of HEK293T cells expressing wild-type hERG channels before or after treated with 1 or 10 µM ALA. n = 6 cells. d, e Representative whole-cell currents and I/V curves of wild-type hERG channels expressed in HEK293T cells treated with DMSO (n = 19) or 20 µM ALA (n = 25) for 24 h. The protocol is shown in the lower right of d, and traces at the time course between two dashed lines are shown. f Dose-dependent effects of long-term ALA treatment on the current densities of wild-type hERG channels recorded at a membrane potential of −140 mV. n ≥ 20 cells per dose were recorded and analyzed. g Western blot analysis of hERG proteins expressed in HEK293T cells treated with DMSO or 20 µM ALA for 24 h (top), and quantitantive analysis of the ratio of fully glycosylated (FG, 155 kD) to total hERG proteins (down). Black and gray arrows indicate 155 kD and 135 kD bands of hERG proteins, respectively. h Immunostaining of hERG and ER marker protein Calnexin in HEK293T cells treated with DMSO or 20 µM ALA for 24 h. Scale bar: 20 µm. Data shown are mean ± s.e.m. **P < 0.01,***P < 0.001 (Student’s t-tests for e, g). All experiments were performed at least three times