Phenylarsine oxide (PAO)-mediated activation of phospholipase D in rat basophilic leukemia (RBL-2H3) cells: possible involvement of calcium and protein kinase C.
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| Abstract |
Addition of phenylarsine oxide (PAO) to [3H]oleic acid-labeled rat basophilic leukemia (RBL-2H3) cells gave rise to the remarkable formation of [3H]phosphatidylbutanol (PBut), a specific product of phospholipase D (PLD) activation. Preincubation of cells with 2,3-dimercaptopropanol (DMP) or dithiothreitol (DTT), compounds containing sulfhydryls, prevented PAO-stimulated [3H]PBut formation, indicating that PAO-stimulated PLD through interacting with vicinal thiol groups. Treatment of cells with PAO resulted in increase in intracellular Ca2+ concentration without significant production of inositol phosphates. Removal of extracellular free Ca2+ by chelating with EGTA was found to inhibit [3H]PBut formation by PAO. Incubation of cells with 20 nM phorbol 12-myristate 13-acetate (PMA) for 6 h caused down-regulation of protein kinase C (PKC) alpha and beta isozymes, whereas it had no effect on PKC delta, epsilon and zeta isozymes. Under this condition, decrease in PAO-stimulated [3H]PBut formation was observed to occur with a concomitant decrease in the level of PKC alpha and beta isozymes. These results suggest that a covalent bridge between vicinal thiol groups of cell surface proteins induced by PAO potentiates PLD activation and that PAO-induced PLD activation is regulated by Ca2+ and PKC alpha and/or beta isozymes.
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| Authors | T Kumada, S Nakashima, Y Nakamura, H Miyata, Y Nozawa |
| Journal | Immunobiology (Immunobiology) Vol. 195 Issue 3 Pg. 347-59 (Aug 1996) ISSN: 0171-2985 [Print] Netherlands |
| PMID | 8877408 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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