ATP-sensitive K+-channel subunits on the mitochondria and endoplasmic reticulum of rat cardiomyocytes.
ATP-sensitive K(+) (K(ATP)) channel subunits on the subcellular structures of rat cardiomyocytes were studied with antibodies against Kir6.1 and Kir6.2. According to the results of Western blot analysis, Kir6.1 was strongly expressed in mitochondrial and microsome fractions, and faintly expressed in cell membrane fraction, whereas Kir6.2 was mainly expressed in the microsome fraction and weakly in cell membrane and mitochondrial fractions. Immunohistochemistry showed that Kir6.1 and Kir6.2 were expressed in the endocardium, atrial and ventricular myocardium, and in vascular smooth muscles. Immunoelectron microscopy revealed that Kir6.1 immunoreactivity was mainly localized in the mitochondria, whereas Kir6.2 immunoreactivity was mainly localized in the endoplasmic reticulum and a few in the mitochondria. Both Kir6.1 and Kir6.2 are candidates of mitochondrial K(ATP) channel subunits. The data obtained in this study will be useful for analyzing the composition of K(ATP) channels of cardiomyocytes and help to understanding the cardioprotective role of K(ATP) channels during heart ischemia.
Department of Anatomy, Akita University School of Medicine, Japan. mzhou@med.akita-u.ac.jp
Ming
M
Zhou
Osamu
O
Tanaka
Masaki
M
Sekiguchi
Hui-Jing
HJ
He
Yukiko
Y
Yasuoka
Hideaki
H
Itoh
Katsumasa
K
Kawahara
Hiroshi
H
Abe
D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis*; D000818:Animals; D015153:Blotting, Western; D003331:Coronary Vessels / Q000378:metabolism; D006321:Heart / Q000033:anatomy & histology; D007150:Immunohistochemistry; D054086:KATP Channels; D008297:Male; D008861:Microsomes / Q000378:metabolism; D008929:Mitochondria, Heart / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000648:ultrastructure; D009928:Organ Specificity; D024661:Potassium Channels, Inwardly Rectifying / Q000096:biosynthesis*; D021122:Protein Subunits / Q000096:biosynthesis; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D000099161:Kcnj11 Channel
D018528:ATP-Binding Cassette Transporters; D054086:KATP Channels; D024661:Potassium Channels, Inwardly Rectifying; D021122:Protein Subunits; D000099161:Kcnj11 Channel; C092520:uK-ATP-1 potassium channel