Delta protein kinase C interacts with the d subunit of the F1F0 ATPase in neonatal cardiac myocytes exposed to hypoxia or phorbol ester. Implications for F1F0 ATPase regulation.
Mitochondrial protein kinase C isozymes have been reported to mediate both cardiac ischemic preconditioning and ischemia/reperfusion injury. In addition, cardiac preconditioning improves the recovery of ATP levels after ischemia/reperfusion injury. We have, therefore, evaluated protein kinase C modulation of the F(1)F(0) ATPase in neonatal cardiac myocytes. Exposure of cells to 3 or 100 nM 4beta-phorbol 12-myristate-13-acetate induced co-immunoprecipitation of delta protein kinase C (but not alpha, epsilon, or zeta protein kinase C) with the d subunit of the F(1)F(0) ATPase. This co-immunoprecipitation correlated with 40+/-3% and 72+/-9% inhibitions of oligomycin-sensitive F(1)F(0) ATPase activity, respectively. We observed prominent expression of delta protein kinase C in cardiac myocyte mitochondria, which was enhanced following a 4-h hypoxia exposure. In contrast, hypoxia decreased mitochondrial zetaPKC levels by 85+/-1%. Following 4 h of hypoxia, F(1)F(0) ATPase activity was inhibited by 75+/-9% and delta protein kinase C co-immunoprecipitated with the d subunit of F(1)F(0) ATPase. In vitro incubation of protein kinase C with F(1)F(0) ATPase enhanced F(1)F(0) activity in the absence of protein kinase C activators and inhibited it in the presence of activators. Recombinant delta protein kinase C also inhibited F(1)F(0) ATPase activity. Protein kinase C overlay assays revealed delta protein kinase C binding to the d subunit of F(1)F(0) ATPase, which was modulated by diacylglycerol, phosphatidylserine, and cardiolipin. Our results suggest a novel regulation of the F(1)F(0) ATPase by the delta protein kinase C isozyme.
Nguyen
Tiffany
T
Department of Pharmacology and Toxicology, School of Medicine, Medical College of Georgia, Augusta, Georgia 30912-2300, USA.
Ogbi
Mourad
M
Johnson
John A
JA
D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D000860:Hypoxia; D008928:Mitochondria / Q000378:metabolism*; D008954:Models, Biological; D011485:Protein Binding; D020033:Protein Isoforms; D011493:Protein Kinase C / Q000378:metabolism; D051745:Protein Kinase C-delta / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D006180:Proton-Translocating ATPases / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000473:pathology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D020033:Protein Isoforms; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D006180:Proton-Translocating ATPases; D013755:Tetradecanoylphorbol Acetate