Mitochondrial ROMK Channel Is a Molecular Component of MitoK ATP
| Autor: | Brian O'Rourke, Anders O. Garlid, Alice S Ho, Agnieszka Sidor, D. Brian Foster, Keith D. Garlid, Jasma Rucker, Ling Chen |
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| Rok vydání: | 2012 |
| Předmět: |
Proteomics
Potassium Channels Time Factors ATP-sensitive potassium channel Physiology Apoptosis CHO Cells Biology Mitochondrion Transfection Mitochondrial Proton-Translocating ATPases Mass Spectrometry Mitochondria Heart Article Necrosis Adenosine Triphosphate Cricetulus Cricetinae Potassium Channel Blockers medicine Animals Humans Myocytes Cardiac RNA Messenger Potassium Channels Inwardly Rectifying Thallium Inner mitochondrial membrane Heart metabolism Diazoxide Potassium channel blocker Potassium channel Rats Cell biology Bee Venoms Animals Newborn Gene Expression Regulation Biochemistry Cytoprotection Mitochondrial Membranes ROMK Cattle RNA Interference Cardiology and Cardiovascular Medicine medicine.drug |
| Zdroj: | Circulation Research. 111:446-454 |
| ISSN: | 1524-4571 0009-7330 |
| DOI: | 10.1161/circresaha.112.266445 |
| Popis: | Rationale: Activation of the mitochondrial ATP-sensitive potassium channel (mitoK ATP ) has been implicated in the mechanism of cardiac ischemic preconditioning, yet its molecular composition is unknown. Objective: To use an unbiased proteomic analysis of the mitochondrial inner membrane to identify the mitochondrial K + channel underlying mitoK ATP . Methods and Results: Mass spectrometric analysis was used to identify KCNJ1(ROMK) in purified bovine heart mitochondrial inner membrane and ROMK mRNA was confirmed to be present in neonatal rat ventricular myocytes and adult hearts. ROMK2, a short form of the channel, is shown to contain an N-terminal mitochondrial targeting signal, and a full-length epitope-tagged ROMK2 colocalizes with mitochondrial ATP synthase β. The high-affinity ROMK toxin, tertiapin Q, inhibits mitoK ATP activity in isolated mitochondria and in digitonin-permeabilized cells. Moreover, short hairpin RNA—mediated knockdown of ROMK inhibits the ATP-sensitive, diazoxide-activated component of mitochondrial thallium uptake. Finally, the heart-derived cell line, H9C2, is protected from cell death stimuli by stable ROMK2 overexpression, whereas knockdown of the native ROMK exacerbates cell death. Conclusions: The findings support ROMK as the pore-forming subunit of the cytoprotective mitoK ATP channel. |
| Databáze: | OpenAIRE |
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