Figure 2.

A, effect of channel deglycosylation on LPS-dependent modulation of I_hHCN2. Cells were left untreated (control) or were incubated with peptide N-glycosidase F (PNGase F, 1000 U ml⁻¹, 37°C, 1 h). Mean V_0.5 recorded under control conditions (open bar, n = 7), in the presence of 50 μg ml⁻¹ LPS (black bar, n = 7), after incubation of cells with PNGase F (light grey bar, n = 7) and in the presence of 50 μg ml⁻¹ LPS after incubation with PNGase F (dark grey bar, n = 7). LPS-dependent modulation of I_hHCN2 is not attenuated by channel deglycosylation. Rather, it sensitizes channels to LPS-dependent modulation because the shift in V_0.5 is augmented after PNGase F treatment of cells. B, a representative Western blot of total lysates from control and PNGase F-treated hHCN2-expressing HEK293 cells. The intensity of the upper band is reduced, whereas a lower band appears by PNGase F treatment, indicating channel deglycosylation. *P < 0.05 versus control; #P < 0.05 versus PNGase F; §P < 0.05 versus LPS.