A, time course of wild-type hBest1 currents recorded from HEK cells pretreated with 100 nm PMA for 2–5 min (circles) or untreated (squares). BIM at 1 μm was applied at the end of recording as indicated by the arrow. B, effect of PMA and myristoylated PKC peptide inhibitor on channel rundown of wild-type and S358A mutant (n= 5–12 cells; *P < 0.05 versus wild-type control; #P < 0.05 versus wild-type with PMA pretreatment by one-way ANOVA). C, time course of S358E mutant current recorded in the presence of 1 μm BIM indicated by the arrow. D, effect of BIM on wild-type and S355E mutant currents. Inhibition was measured as the percentage of the current amplitude 2 min after application of BIM to the amplitude just before BIM application (n= 5–6 cells; *P < 0.05 versus wild-type by one-way ANOVA). E, effects of forskolin and cAMP on channel rundown. Forskolin at 5 μm was applied in the bath solution and 100 μm cAMP was applied in the path pipette (n= 5–13 cells). Channel rundown (B, E and F) was measured as described in Fig. 1.