Regulation of phospholipase D2 by H(2)O(2) in PC12 cells.
Phospholipase D2 (PLD2) is expressed in brain and inhibited by synuclein, which is involved in Parkinson's and Alzheimer's diseases. However, the activation mechanism of PLD2 in neuronal cells has not been defined clearly. Hydrogen peroxide (H(2)O(2)) plays roles in the neurodegenerative diseases and also acts as a second messenger of various molecules such as nerve growth factor. To study regulation mechanisms of PLD2 by H(2)O(2) in neuronal cells, we have made stable PC12 cell lines expressing PLD2 (PLD2-PC12 cells). H(2)O(2) treatment stimulated PLD activity in PLD2-PC12 cells in a dose- and time-dependent manner. This activation was inhibited by the treatment with protein kinase C (PKC) inhibitors or by depletion of PKCalpha, -delta, and -epsilon. Phorbol ester markedly activated PLD2. Co-treatment with phorbol ester and H(2)O(2) did not show an additive effect. Chelation of extracellular calcium substantially blocked the H(2)O(2)-induced activation of PLD2. A calcium ionophore induced PLD2 activation in a PKC-dependent manner. Protein-tyrosine kinase inhibitors inhibited H(2)O(2)-induced PLD activation slightly. These data indicate that H(2)O(2) can activate PLD2 in PC12 cells and that this activation is largely dependent on PKC and Ca(2+) ions and minimally dependent on tyrosine phosphorylation.
Oh
S O
SO
Department of Biochemistry, College of Medicine, Chungnam National University, Taejeon, Korea.
Hong
J H
JH
Kim
Y R
YR
Yoo
H S
HS
Lee
S H
SH
Lim
K
K
Hwang
B D
BD
Exton
J H
JH
Park
S K
SK
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016716:PC12 Cells; D010739:Phospholipase D / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D004791:Enzyme Inhibitors; D007527:Isoenzymes; D006861:Hydrogen Peroxide; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; C105606:phospholipase D2; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium