title: Subunit composition of ATP-sensitive potassium channels in mitochondria of rat hearts.
abstract: Mitochondrial ATP-sensitive potassium (mitoKATP) channels play a pivotal role in early and late ischemic preconditioning, but the subunit composition of mitoKATP channels remains unclear. In this study, we investigated the subunit composition of mitoKATP channels in rat hearts using confocal microscopy, immunofluorescence, and Western blot analysis. The green fluorescent probe glibenclamide-BODIPY was colocalized with the red fluorescent mitochondrial marker MitroTracker Red in isolated ventricular myocytes and in ventricular myocyte mitochondria, indicating the presence of sulfonylurea receptors (SURs) in the mitochondria. Anti-Kir6.1, anti-Kir6.2, and anti-SUR2 immunofluorescence was colocalized with that of MitoTracker Red in isolated mitochondria, suggesting that Kir6.1, Kir6.2, and SUR2 subunits are present in the mitochondria. Similarly, Kir6.1 (approximately 46 kDa), Kir6.2 (approximately 46 and approximately 40 kDa), and SUR2 (approximately 140 kDa) proteins were found to be expressed in mitochondria using Western blot analysis. By contrast, SUR1 was not present in mitochondria. These results suggest that mitoKATP channels in rat hearts might comprise a combination of Kir6.1, Kir6.2, and SUR2 subunits.
authors.affiliation: Department of Physiology and Biophysics, Mitochondrial Signaling Laboratory, College of Medicine, Biohealth Products Research Center, Inje University, 633-165 Gaegeum-Dong, Busanjin-Ku, Busan 614-735, South Korea.
authors.forename: Dang Van
authors.initials: DV
authors.lastname: Cuong
authors.forename: Nari
authors.initials: N
authors.lastname: Kim
authors.forename: Hyun
authors.initials: H
authors.lastname: Joo
authors.forename: Jae Boum
authors.initials: JB
authors.lastname: Youm
authors.forename: Joon-Yong
authors.initials: JY
authors.lastname: Chung
authors.forename: Youngsuk
authors.initials: Y
authors.lastname: Lee
authors.forename: Won Sun
authors.initials: WS
authors.lastname: Park
authors.forename: Euiyong
authors.initials: E
authors.lastname: Kim
authors.forename: Young Shik
authors.initials: YS
authors.lastname: Park
authors.forename: Jin
authors.initials: J
authors.lastname: Han
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D001896:Boron Compounds; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D054086:KATP Channels; D018613:Microscopy, Confocal; D008929:Mitochondria, Heart / Q000378:metabolism*; D009930:Organic Chemicals; D024661:Potassium Channels, Inwardly Rectifying / Q000737:chemistry* / Q000378:metabolism*; D021122:Protein Subunits; D051381:Rats; D011955:Receptors, Drug; D064233:Sulfonylurea Receptors; D000099161:Kcnj11 Channel
chemical_list: D018528:ATP-Binding Cassette Transporters; D000255:Adenosine Triphosphate; D001896:Boron Compounds; D005456:Fluorescent Dyes; D054086:KATP Channels; D009930:Organic Chemicals; D024661:Potassium Channels, Inwardly Rectifying; D021122:Protein Subunits; D011955:Receptors, Drug; D064233:Sulfonylurea Receptors; D000099161:Kcnj11 Channel; C095489:4,4-difluoro-4-bora-3a,4a-diaza-s-indacene; C577509:Abcc8 protein, rat; C577512:Abcc9 protein, rat; C107472:red dye CMXRos; C092520:uK-ATP-1 potassium channel