FIGURE 2.

The V223L mutation accelerates the gating kinetics of Kir2. A, dose response of diC8 PIP₂ of Kir2.1 and V223L, showing a right shift in the apparent affinity of PIP₂ sensitivity as a result of the mutation. B, peak currents of Kir2.1 and V223L do not show a decrease in whole-cell current, as other mutations do, that decrease the apparent channel affinity to PIP₂. C, the representative time course of inhibition (PIP₂ dephosphorylation induced by Ci-VSP, a 3.7-fold effect) and reactivation (PIP₂ rephosphorylation, a 2.5-fold effect) of WT-Kir2.1 and V223L. D, bars are the time constants (mean ± S.E. of at least six experiments) corresponding to C.