A high Kvβ:Kv1.2 transfection ratio does not cause accelerated inactivation and does not prevent functional effects of Slc7a5 . (A) LM cells were transfected with Kv1.2(T252R) and Kvβ in the absence or presence of mCherry Slc7a5. Transfection ratios were (with Kv1.2 maintained constant using GFP) Kv1.2:Kvβ, 1:10; Kv1.2:Kvβ:Slc7a5, 1:10:0.5. Cells were hyperpolarized to −120 mV for 30 s before recording to disinhibit Kv1.2 currents. Time constants of inactivation (τ inact) were calculated from a single exponential fit of the inactivating current at depolarizing sweeps from 50 to 110 mV in 10-mV increments for 100 ms from a −100-mV holding potential (mean ± SEM; n = 7–12 individual cells recorded for each group). (B) τ Inactivation of individual cells from each group in A were obtained from the inactivating currents at +100 mV from a −100-mV holding voltage (n = 7–12 individual cells recorded for each group). Student’s t test was used to compare the Slc7a5 treatment group versus the respective control; P values are denoted above the box plots. Box plots depict the median, 25th, and 75th percentiles (box) and the 10th and 90th percentiles (whiskers).