TY - JOUR
T1 - Delta protein kinase C interacts with the d subunit of the F 1F0 ATPase in neonatal cardiac myocytes exposed to hypoxia or phorbol ester
T2 - Implications for F1F0 ATPase regulation
AU - Nguyen, Tiffany
AU - Ogbi, Mourad
AU - Johnson, John A.
PY - 2008/10/31
Y1 - 2008/10/31
N2 - 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 F1F0 ATPase in neonatal cardiac myocytes. Exposure of cells to 3 or 100 nM 4β-phorbol 12-myristate-13- acetate induced co-immunoprecipitation of δ protein kinase C (but not α, ε, or ζ protein kinase C) with the d subunit of the F 1F0 ATPase. This co-immunoprecipitation correlated with 40 ± 3% and 72- ± 9% inhibitions of oligomycin-sensitive F 1F0 ATPase activity, respectively. We observed prominent expression of δ protein kinase C in cardiac myocyte mitochondria, which was enhanced following a 4-h hypoxia exposure. In contrast, hypoxia decreased mitochondrial ζPKC levels by 85 ± -1%. Following 4 h of hypoxia, F1F0 ATPase activity was inhibited by 75 ± -9% and δ protein kinase C co-immunoprecipitated with the d subunit of F 1F0 ATPase. In vitro incubation of protein kinase C with F1F0 ATPase enhanced F1F0 activity in the absence of protein kinase C activators and inhibited it in the presence of activators. Recombinant δ protein kinase C also inhibited F 1F0 ATPase activity. Protein kinase C overlay assays revealed δ protein kinase C binding to the d subunit of F 1F0 ATPase, which was modulated by diacylglycerol, phosphatidylserine, and cardiolipin. Our results suggest a novel regulation of the F1F0 ATPase by the δ protein kinase C isozyme.
AB - 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 F1F0 ATPase in neonatal cardiac myocytes. Exposure of cells to 3 or 100 nM 4β-phorbol 12-myristate-13- acetate induced co-immunoprecipitation of δ protein kinase C (but not α, ε, or ζ protein kinase C) with the d subunit of the F 1F0 ATPase. This co-immunoprecipitation correlated with 40 ± 3% and 72- ± 9% inhibitions of oligomycin-sensitive F 1F0 ATPase activity, respectively. We observed prominent expression of δ protein kinase C in cardiac myocyte mitochondria, which was enhanced following a 4-h hypoxia exposure. In contrast, hypoxia decreased mitochondrial ζPKC levels by 85 ± -1%. Following 4 h of hypoxia, F1F0 ATPase activity was inhibited by 75 ± -9% and δ protein kinase C co-immunoprecipitated with the d subunit of F 1F0 ATPase. In vitro incubation of protein kinase C with F1F0 ATPase enhanced F1F0 activity in the absence of protein kinase C activators and inhibited it in the presence of activators. Recombinant δ protein kinase C also inhibited F 1F0 ATPase activity. Protein kinase C overlay assays revealed δ protein kinase C binding to the d subunit of F 1F0 ATPase, which was modulated by diacylglycerol, phosphatidylserine, and cardiolipin. Our results suggest a novel regulation of the F1F0 ATPase by the δ protein kinase C isozyme.
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U2 - 10.1074/jbc.M801642200
DO - 10.1074/jbc.M801642200
M3 - Article
C2 - 18725417
AN - SCOPUS:57649223697
SN - 0021-9258
VL - 283
SP - 29831
EP - 29840
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 44
ER -