Ghasemi M, Khodaee ataloo N, Khodagholi F, Eliassi A. A molecular study on the endoplasmic reticulum potassium channels in hepatocytes. Physiol Pharmacol 2014; 18 (3) :304-314
URL:
http://ppj.phypha.ir/article-1-1012-en.html
Abstract: (6266 Views)
Introduction: It has recently been suggested that the KATP channel subunits Kir6.x and BKCa channels exist in the
endoplasmic reticulum of cardiomyocytes and neurons. Our previous studies showed the electrophysiological behavior
of cation channels in the rough endoplasmic reticulum (RER) of rat hepatocytes. Therefore, we hypothesized that KATP
channels and Ca2+-activated potassium channels may exist in RER of the liver.
Methods: Ion channel incorporation of RER of hepatocytes into the bilayer lipid membrane and western blotting
allowed the identification of the rerKATP and Ca2+-activated potassium channels of intermediate conductance (rerIKCa
channel).
Results: Single channel recordings revealed a 211 pS K channel, which was sensitive to 200 nM charibdotoxin. In
addition, adding 2.5 mM ATP, 100 μM glibenclamide and 400 μM tolbutamide inhibited a 596 pS potassium channel
activity. According to the results of western blot analysis, Kir6.2, SUR1 and/or SUR2B, SUR2A and IKCa were
expressed in the endoplasmic reticulum fractions.
Conclusion: The data obtained in this study demonstrate, in part, the composition of rerKATP channel and the
presence of rerIKCa in the endoplasmic reticulum of the liver. These results will be useful for further analysis of the
composition of rerKATP and rerIKCa channels and help to understand the role of these channels in diseases.