Activation of phospholipases D and A by amphiphilic cations of cultured LA-N-2 cells is G protein- and protein kinase C-independent.
Several amphiphilic cations such as mepacrine, desipramine, didodecyldimethylamine, chlorpromazine, oleylamine and W-7 activated the phospholipase D (PLD) activity of cultured LA-N-2 cells. These compounds, except for oleylamine, provoked the release of fatty acids, suggesting phospholipase A activation. Melittin, a PLA2 stimulator, caused the robust release of the free fatty acids but was a poor PLD activator. Although PLD could be activated by GTP gamma S, the stimulation by these amphiphilic cations was not abolished by GDP beta S, an inhibitor of G protein function. There was no change in the PLD activation by these amphiphilic cations by DiC8, a PKC activator, or by H-7, a PKC inhibitor or in PKC down-regulated cells.
Singh
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IN
Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Canada.
Massarelli
R
R
Kanfer
J N
JN
D000588:Amines / Q000494:pharmacology; D001345:Autoradiography; D002412:Cations / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000502:physiology*; D006801:Humans; D008555:Melitten / Q000494:pharmacology; D010739:Phospholipase D / Q000187:drug effects* / Q000378:metabolism; D010741:Phospholipases A / Q000187:drug effects* / Q000378:metabolism; D054467:Phospholipases A2; D011493:Protein Kinase C / Q000502:physiology*; D014407:Tumor Cells, Cultured
D000588:Amines; D002412:Cations; D005230:Fatty Acids, Nonesterified; D008555:Melitten; D011493:Protein Kinase C; D010741:Phospholipases A; D054467:Phospholipases A2; D010739:Phospholipase D; D019204:GTP-Binding Proteins