XB-IMG-148477
Xenbase Image ID: 148477
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Fig. S5. KCNE1 exerts multiple parallel effects on KCNQ1 currents. (A) KCNQ1 was expressed alone or coinjected with KCNE1 mRNA at two concentrations (0.02
ng of KCNE1 mRNA per oocyte; 2 ng of KCNE1 mRNA per oocyte). Representative current traces at voltages indicated are shown. At a low concentration (0.02
ng of KCNE1 mRNA per oocyte), currents activate faster and result in larger currents after 7 sec compared with currents resulting from KCNQ1 coinjected with
a 100-fold larger KCNE1 concentration (2 ng of KCNE1 mRNA per oocyte), indicating that high KCNE1 expression can suppress currents. (B) The currents shown
in A at 60 mV are plotted on top of each other. Scaling of current amplitudes is as in A. Under these conditions it is clear that channel currents are smaller due
to coexpression of KCNE1 with KCNQ1 in the first phase and depending on the amount of KCNE1 coinjected (a vs. b, phase of KCNE1 suppression at 0.02 ng of
KCNE1 mRNA per oocyte indicated by vertical striation 3 about 0.4 sec; a vs. c, phase of KCNE1 suppression at 2 ng of KCNE1 mRNA per oocyte indicated by
horizontal striation 3 about 2 sec). (C) Peak currents were analyzed at the end of the 7-sec pulses and plotted vs. the respective voltage (n 10–11). KCNQ1
channels were expressed alone or together with KCNE1 mRNA. (D) Oocytes were injected with 5 ng of KCNQ1 2 ng of KCNE1 mRNA. Peak channel currents
at 60 mV, 0 mV, and 60 mV were normalized to the peak currents of KCNQ1 expressed alone at the respective voltage (normalized value of 1 indicates no
change from KCNQ1 alone; normalized value of 0 indicates inhibition of current). These data indicate that K currents are suppressed by KCNE1 at voltages
below 0 mV. Image published in: Morokuma J et al. (2008) Copyright © 2008. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License. Larger Image Printer Friendly View |