Fig. 2

Overexpression of KCNJ2 in iPSC-CMs gives rise to enhanced IK1. a Bar graph to compare the mRNA expression of KCNJ2 between human heart tissues and iPSC-CMs. n = 6 different human heart tissues or different iPSC lines. b iPSC-CMs were transduced with GFP only (negative control, Vector OE) or Kir2.1 protein labeled with GFP (KCNJ2-GFP, KCNJ2 OE) using the lentiviral transfection system. 72 h after transfection, the representative graphs were captured to reveal the high level of overexpression. GFP indicates successfully transfected cells. The images were captured by an inverted fluorescence microscope (Nikon ECLIPSE Ti-S). Scale bar, 100 μm. c Kir2.1 protein abundance was evaluated among untreated, Vector OE and KCNJ2 OE iPSC-CMs by Western blot analysis. Full-length blots are presented in Additional file 1: Figure 2. d Representative current tracings of IK1 recorded from Vector OE and KCNJ2 OE iPSC-CMs by single-cell patch clamp at − 120 mV. e I–V plots of IK1 of Vector OE and KCNJ2 OE iPSC-CMs by single-cell patch clamp recordings from − 120 to + 20 mV. f Bar graph to compare the current density of IK1 between Vector OE (n = 8 cells) and KCNJ2 OE (n = 6 cells) iPSC-CMs at − 120 mV