Effects of PIP₂ on Slo1 complexes with different subunit compositions. (A) Illustrative currents through Slo1, Slo1 + β1, Slo1 + β2, Slo1 + β2 Δ2–19, Slo1 + β4, and Slo1 + LRRC26 (γ1). In each panel, currents before (blue) and after (red) the application of 10 µM PIP₂ to the cytoplasmic side recorded without Ca²⁺ are shown. Pulses were applied from 0 mV every 3 s except for Slo1 + β2, which was stimulated every 10 s. For Slo1 + β2, 1-s prepulses to −100 mV preceded depolarization pulses. For Slo1 + LRRC26 (γ1), the holding voltage was −80 mV. (B) Fractional changes in peak outward currents in Slo1, Slo1 + β1, Slo1 + β2, Slo1 + β2 Δ2–19, Slo1 + β4, and Slo1 + LRRC26 (γ1). (C) Normalized conductance (G-V) curves before (blue) and after (red) the application of 10 µM PIP₂ in the channels indicated. The smooth curves are Boltzmann fits to the results with: Slo1, V_0.5 = 154.5 ± 3.1 mV and Q_app = 1.33 ± 0.04 (Control), and 170.1 ± 2.7 mV and 1.18 ± 0.05 (PIP₂); Slo1 + β1, V_0.5 = 167.8 ± 2.0 mV and Q_app = 0.92 ± 0.02 (Control), and 122.3 ± 2.8 mV and 0.95 ± 0.03 (PIP₂); Slo1 + β2 Δ2–19, V_0.5 = 163.9 ± 3.0 mV and Q_app = 0.98 ± 0.02 (Control), and 158.6 ± 2.4 mV and 0.92 ± 0.02 (PIP₂); Slo1 + β4, V_0.5 = 217.2 ± 3.2 mV and Q_app = 0.99 ± 0.03 (Control), and 183.2 ± 4.0 mV and 1.00 ± 0.03 (PIP₂); and Slo1 + LRRC26 (γ1), V_0.5 = 20.9 ± 3.5 mV and Q_app = 1.38 ± 0.06 (Control), and 42.3 ± 1.8 mV and 1.09 ± 0.04 (PIP₂); n = 9–18. Error bars represent mean ± SEM.