Role of protein kinase C-alpha in activation of ecto-5'-nucleotidase in the preconditioned canine myocardium.
We have reported that activation of protein kinase C (PKC) increases ecto-5'-nucleotidase activity, which may contribute to the infarct size-limiting effect of ischemic preconditioning. Since we have reported that Ca(2+)- and phospholipid-sensitive PKC is activated due to ischemic preconditioning, we further tested 1) whether PKC-alpha or -beta is translocated to the cellular membrane of the preconditioned canine myocardium, and 2) whether activation of PKC contributes to the increase in ecto-5'-nucleotidase activity via phosphorylation-dependent mechanisms. Four times of 5 minutes coronary occlusion separated by 5 minutes of reperfusion (ischemic preconditioning) translocated PKC-alpha to the cellular membrane in the canine hearts, although PKC-beta, -delta, -epsilon, and -zeta were not translocated. The activity of Ca(2+)- and phospholipid-sensitive PKC increased, which was attenuated by the removal of either Ca2+ or phosphatidylserine. Ecto-5'-nucleotidase was also activated in the preconditioned myocardium compared with control. Inhibition of PKC due to GF109203X blunted the activation of myocardial ecto-5'-nucleotidase. Okadaic acid (an inhibitor of phosphatase) enhanced the increases in ecto-5'-nucleotidase activity due to preconditioning, and this enhancement was blunted by GF109203X. We conclude that ischemic preconditioning activates PKC-alpha, and thus ecto-5'-nucleotidase.
Kitakaze
M
M
First Department of Medicine, Osaka University School of Medicine, Suita, Japan. kitakaze@medone.med.osaka-u.ac.jp
Funaya
H
H
Minamino
T
T
Node
K
K
Sato
H
H
Ueda
Y
Y
Okuyama
Y
Y
Kuzuya
T
T
Hori
M
M
Yoshida
K
K
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport; D001794:Blood Pressure; D002462:Cell Membrane / Q000201:enzymology; D004285:Dogs; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006339:Heart Rate; D007211:Indoles / Q000494:pharmacology; D019157:Ischemic Preconditioning, Myocardial; D007527:Isoenzymes / Q000378:metabolism*; D008301:Maleimides / Q000494:pharmacology; D008729:Methoxamine / Q000494:pharmacology; D009206:Myocardium / Q000201:enzymology*; D019319:Okadaic Acid / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D004791:Enzyme Inhibitors; D007211:Indoles; D007527:Isoenzymes; D008301:Maleimides; D019319:Okadaic Acid; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D000251:Adenosine Triphosphatases; C027201:ectoATPase; D008729:Methoxamine; C070515:bisindolylmaleimide I; D013755:Tetradecanoylphorbol Acetate; D011224:Prazosin