Figure 5. Foxo1 inhibits Na⁺ channel activity.

Foxo1-AA-GFP was localized in HL-1 cardiomyocyte nuclei (B) while GFP was seen in both nuclei and cytoplasm (A). Whole cell Na⁺ currents were recorded during 80 ms depolarizing voltage steps to potentials between −60 and +60 mV from a holding potential of −100 mV in HL-1 cells expressing GFP or Foxo1-AA-GFP for 36 hours. The typical whole cell recording traces showed that robust Na⁺ currents were present in HL-1 cells expressing GFP (C) while remarkable reduction of Na⁺ currents in these cells expressing Foxo1-AA-GFP (D).