Detection of Mitochondrial ATP-Sensitive Potassium Channels in Rat Cardiomyocytes

  • Cuong, Dang Van (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Kim, Na-Ri (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Kim, Eui-Yong (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Lee, Young-Suk (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Kim, Hyun-Ju (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Kang, Sung-Hyun (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Hur, Dae-Young (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Joo, Hyun (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Park, Young-Shik (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Hong, Yong-Geun (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Lee, Sang-Kyung (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Chung, Joon-Yong (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Seog, Dae-Hyun (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University) ;
  • Han, Jin (Department of Physiology and Biophysics, College of Medicine, and 2020 Cardiovascular Institute, Inje University)
  • Published : 2004.08.21

Abstract

Mitochondrial ATP-sensitive potassium $(mitoK_{ATP})$ channels play a role in early and late ischemic preconditioning. Nevertheless, the subunit composition of $mitoK_{ATP}$ channels remains unclear. In this study, we investigated the subunit composition of $mitoK_{ATP}$ channels in mitochondria isolated from rat cardiac myocytes. Mitochondria were visualized using the red fluorescence probe, Mitrotracker Red, while $mitoK_{ATP}$ channels were visualized using the green fluorescence probe, glibenclamide-BODIPY. The immunofluorescence confocal microscopy revealed the presence of Kir6.1, Kir6.2 and SUR2 present in the cardiac mitochondria. Western blot analysis was carried to further investigate the nature of $mitoK_{ATP}$ channels. For SUR proteins, a 140-kDa immunoreactive band that corresponded to SUR2, but no SUR1 was detected. For Kir6.2, three bands $({\sim}44,\;{\sim}46,\;and\;{\sim}30\;kDa)$ were detected, and a specific ${\sim}46-kDa$ immunoreactive band corresponding to Kir6.1 was also observed. These observations suggest that the subunits of $mitoK_{ATP}$ channels in rat myocytes include Kir6.1, Kir6.2, and a SUR2-related sulfonylurea-binding protein.

Keywords

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