Role of protein kinase C alpha in nerve growth factor-induced arachidonic acid release from PC12 cells.
Nerve growth factor (NGF) increases arachidonic acid (AA) release by PC12 pheochromocytoma cells. To explore the role of protein kinase C (PKC) in this action of NGF, PKC was down-regulated by long-term treatment of the cells with phorbol 12-myristate 13-acetate (PMA). Such prolonged exposure to PMA (1 microM) resulted in the inhibition of NGF-induced AA release. Moreover, pretreatment of PC12 cells with the protein kinase inhibitor staurosporine or with calphostin C, a specific inhibitor of PKC, also blocks the increase of AA release induced by NGF. These data, as well as that PMA alone can induce AA release in PC12 cells, suggest that PKC is necessary for NGF-induced AA release. Immunoblot analysis of whole cell lysates by using antibodies against various PKC isoforms revealed that our PC12 cells contained PKCs alpha, delta, epsilon, and zeta. PMA down-regulation depleted PKCs alpha, delta, and epsilon, and partially depleted zeta. To see which isoform was involved in NGF-induced AA release, an isoform-specific PKC inhibitor was used. GO 6976, a compound that inhibits PKCs alpha and beta specifically, blocked NGF-induced AA release. In addition, thymeleatoxin, a specific activator of PKCs alpha, beta, and gamma, induced AA release from PC12 cells in amounts comparable with those seen with NGF. Taken together, these data suggest that PKC alpha plays a role in NGF-induced AA release.
Zheng
W H
WH
Section on Growth Factors, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
Fink
D W
DW
Guroff
G
G
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism*; D004789:Enzyme Activation; D007527:Isoenzymes / Q000502:physiology*; D009414:Nerve Growth Factors / Q000494:pharmacology*; D016716:PC12 Cells / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007527:Isoenzymes; D009414:Nerve Growth Factors; D016718:Arachidonic Acid; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate