Figure 2.

Activation of RhoA triggers Kv1.2 endocytosis. (A) Application of increasing concentrations of LPA (15 min) significantly reduces the level of Kv1.2 at the cell surface in a concentration-dependent manner as detected by flow cytometry (n = 5′ *p < 0.05, **p < 0.01). (B) Average whole-cell currents evoked in HEK-K cells with pulses from −70 to +50 mV in increments of 10 mV in the presence of saline or LPA (10 μM; 15 min). LPA application significantly reduces mean whole-cell currents. Current traces for each condition represent the average of at least 11 cells (n ≥11; p < 0.01). (C) Pretreatment of HEK-K cells with C3 exoenzyme (2 μg/ml; 6 h) significantly increases steady-state surface Kv1.2 (n = 9; **p = 0.028). LPA caused a significant decrease in surface Kv1.2 levels in control cells (C) (n = 9; *p < 0.001) but had no significant effect in cell pre-treated with C3 exoenzyme (n = 9, p = 0.37). (D) In HEK-K cells, LPA application results in translocation of Kv1.2 (green) from the RhoA and actin rich edge of the cell (left column) to intracellular puncta that contain EEA1 or are adjacent to EEA1-containing structures (right column).