Figure 5. Hypertonic solutions inhibited hBest1 currents through dephosphorylation of S358.

A, effects of hypertonic solutions (1.2 T, 365 mosmol l⁻¹) on wild-type hBest1 currents recorded from control cell (squares), cell pretreated with 1 μm PMA (circles) or 1 μm okadaic acid (triangles). B, hypertonic solution had no effect on the current induced by S358E mutation. Hypertonic solution was applied when current reached peak amplitude as indicated by the arrow (A and B). C, effects of OA, PMA and S358E mutation on hypertonic inhibition of hBest1 currents. The channel rundown was measured as ratio of amplitudes of the current 2 min (open columns) or 5 min (filled columns) after hypotonic solution was applied at the peak to the amplitudes at the peak (n= 5–10 cells; *P < 0.05 versus wild-type control).