Fig. 4. Coexpression of KCNQ1wt(wt) and KCNQ1A344V(A344V) channels in the presence (+ E1) and absence (− E1) of KCNE1 in Xenopus laevis oocytes. Equal amounts of KCNQ1wtand KCNQ1A344Vcomplementary RNA (cRNA) were injected without or with KCNE1 cRNA. Family of current traces evoked by the activation protocol through KCNQ1wt/KCNQ1A344Vchannels ( A ) and KCNQ1wt/KCNQ1A344V/KCNE1 channel complexes ( B ). ( C ) Voltage dependence of activation of heteromeric KCNQ1wt/KCNQ1A344Vchannels. Boltzmann fits of the homomeric channels were added for comparison. ( D ) Inhibition of KCNQ1wt/KCNQ1A344Vand KCNQ1wt/KCNQ1A344V/KCNE1 channels by 100 μm bupivacaine. ( E ) Comparison of inhibition of homomeric and heteromeric channels by 100 μm bupivacaine. * Significant difference between channels without and with KCNE1. n.s. = not significant.