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SYNERGISTIC ACTIVATION OF PHOSPHOLIPASE-D BY PROTEIN KINASE-C-PROTEIN-MEDIATED AND G-PROTEIN-MEDIATED PATHWAYS IN STREPTOLYSIN-O-PERMEABILIZED HL-60 CELLS

GENY, B; COCKCROFT, S; (1992) SYNERGISTIC ACTIVATION OF PHOSPHOLIPASE-D BY PROTEIN KINASE-C-PROTEIN-MEDIATED AND G-PROTEIN-MEDIATED PATHWAYS IN STREPTOLYSIN-O-PERMEABILIZED HL-60 CELLS. BIOCHEM J , 284 531 - 538.

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Abstract

Stimulation of phospholipase D (PLD) by cell surface receptors has been observed in many cell types. We have investigated the mechanism of activation of this enzyme in undifferentiated HL60 cells. GTP analogues and Ca2+ (buffered in the nanomolar to micromolar range) were introduced into HL60 cells in the presence of the permeabilizing agent. streptolysin 0. We report that guanosine 5'-[gamma-thio]triphosphate (GTP[S]) is a potent activator of phospholipase D when Ca2+ is available at micromolar levels. Phorbol 12-myristate 13-acetate or Ca2+ alone can also stimulate PLD, but to a limited extent. The activation of PLD by GTP[S] can be partially dissociated from GTP[S]-stimulated phosphoinositide-specific phospholipase C, suggesting that a G-protein may be directly involved in regulating PLD. However, maximal activation of PLD only occurs under conditions that are permissive to phospholipase C stimulation. We conclude that PLD activation is under dual control, i.e. protein kinase C- as well as G-protein-mediated regulation. Synergistic activation occurs when both pathways are simultaneously stimulated. We conclude that full activation of PLD requires protein kinase C, increased Ca2+ and a GTP-binding protein. Evidence for cytosolic components that may also be involved in obtaining full activation of PLD is also presented.

Type: Article
Title: SYNERGISTIC ACTIVATION OF PHOSPHOLIPASE-D BY PROTEIN KINASE-C-PROTEIN-MEDIATED AND G-PROTEIN-MEDIATED PATHWAYS IN STREPTOLYSIN-O-PERMEABILIZED HL-60 CELLS
Keywords: POLYPHOSPHOINOSITIDE PHOSPHODIESTERASE, ENDOTHELIAL-CELLS, EXOCYTOTIC SECRETION, GUANINE-NUCLEOTIDES, HL-60 GRANULOCYTES, HUMAN-NEUTROPHILS, POTENTIAL ROLE, MAST-CELLS, PHOSPHATIDYLCHOLINE, PHOSPHATIDATE
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences > Neuro, Physiology and Pharmacology
URI: http://discovery.ucl.ac.uk/id/eprint/67894
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