Figure 1. Effect of Klotho coexpression on current in KCNQ1/KCNE1 expressing Xenopus oocytes. (A) Original tracings demonstrating outward K⁺ currents activated by depolarization from -120 to +80 mV in 20 mV steps from a holding potential of -80 mV in Xenopus oocytes injected with water (1), injected with cRNA encoding KCNQ1/KCNE1 (2) and in Xenopus oocytes injected with cRNA encoding KCNQ1/KCNE1 and Klotho (3). (B) Arithmetic means ± SEM (n = 16–57) of the normalized depolarization-induced K⁺ current at +80 mV in Xenopus oocytes injected with water (dotted bar), with cRNA encoding KCNQ1/KCNE1(white bar) or with cRNA encoding KCNQ1/KCNE1 and Klotho (black bar). *** indicates statistically significant (P < 0.001) difference of KCNQ1/KCNE1 and Klotho expressing Xenopus oocytes from Xenopus oocytes expressing KCNQ1/KCNE1 alone. (C) Arithmetic means ± SEM (n = 16–57) of the normalized depolarization-induced K⁺ current as a function of voltage in Xenopus oocytes injected with water (gray triangles), with cRNA encoding KCNQ1/KCNE1 (white circles) or with cRNA encoding KCNQ1/KCNE1 and Klotho (black circles). *** indicates statistically significant (P < 0.001) difference of KCNQ1/KCNE1 and Klotho expressing Xenopus oocytes from Xenopus oocytes expressing KCNQ1/KCNE1 alone. (D) Arithmetic means ± SEM (n = 56–57) of the normalized depolarization-induced K⁺ current to the maximum peak current of each respective group as a function of voltage in Xenopus oocytes injected with cRNA encoding KCNQ1/KCNE1 (white circles) or with cRNA encoding KCNQ1/KCNE1 and Klotho (black circles).