Figure 5.

Constitutive-conducting phenotype for the P406D mutant in the Kv2.1 channel. (A) Family of ionic currents for Kv2.1 Δ7 and P406D Kv2.1 Δ7. Depolarizations were from −70 to +20 mV (10-mV increments) for Kv2.1 Δ7 and from −110 to −10 mV (10-mV increments) for P406D Kv2.1 Δ7. Charge carrier in the external solution was 50 mM Rb⁺. Linear capacity and background conductances were identified and subtracted by blocking the Kv2.1Δ7 channel with Agitoxin-2. Horizontal dashed lines correspond to the zero current level. (B) G-V relations obtained by plotting normalized tail current amplitudes against test voltage. Same cells as in A. Smooth curves are single Boltzmann fits to the data with parameters as follows: Kv2.1 Δ7, V₅₀ = −1.1 mV, z = 2.7; P406D Kv2.1 Δ7, V₅₀ = −52 mV, z = 2.7.