Figure 6. Depletion of PtdIns(4,5)P2 mimics the effect of the mild cholesterol enrichment. (A) Averaged current-voltage relations were measured at the end of the depolarizing step following the step to −40 mV as described in Figure 1C (Istep). Either control antibody (Cont Ab; n = 4) or anti-PtdIns(4,5)P2 antibody [PtdIns(4,5)P2 Ab; n = 7] was included in the intracellular pipette solution (1/100 dilution). For the effective sequestering of PtdIns(4,5)P2 by anti-PtdIns(4,5)P2 antibody, recordings of HERG current were started 10 min after obtaining whole-cell configuration. The inset shows voltage-dependent activation curve for Istep obtained by normalizing the current by the maximum currents. (B) The time course of HERG channel activation was analyzed as described in Figure 5B. *p < 0.05; **p < 0.01.