Tumour‐promoting phorbol esters inhibit agonist‐induced phosphatidate formation and Ca2+ flux in human platelets
- 28 January 1985
- journal article
- Published by Wiley in FEBS Letters
- Vol. 180 (2) , 160-164
- https://doi.org/10.1016/0014-5793(85)81063-2
Abstract
Tumour-promoting phorbol esters (phorbol-12-myristate-13-acetate, PMA; phorbol-12,13-dibutyrate, PDBu) but not 4β-phorbol, activate protein kinase C. Using human platelets pre-labelled with quin2 or 32PO4 we examined the effects of these compounds on human platelet cytosolic free Ca2+ ([Ca2+]j) and on [32]phosphatidic acid ([32P]PtdOH). PMA and PDBu, but not 4β-phorbol inhibited thrombin-, PAF- and vasopressin-induced elevation of [Ca2+], and [2+P]PtdOH formation. It is suggested that protein kinase C may act to terminate the transduction processes that link receptor occupancy to cellular activation.Keywords
This publication has 26 references indexed in Scilit:
- 12‐O‐Tetradecanoylphorbol 13‐acetate stimulates inositol lipid phosphorylation in intact human plateletsFEBS Letters, 1984
- A comparison of the effects of soluble stimuli on free cytoplasmic and membrane bound calcium in human neutrophilsCell Calcium, 1984
- Activation of protein kinase C by a tumor‐promoting phorbol ester in pancreatic isletsFEBS Letters, 1984
- Prostacyclin inhibition of phosphatidic acid synthesis in human platelets is not mediated by protein kinase CBiochemical and Biophysical Research Communications, 1984
- Release of Ca2+ from a nonmitochondrial intracellular store in pancreatic acinar cells by inositol-1,4,5-trisphosphateNature, 1983
- The phorbol ester TPA increases the affinity of exocytosis for calcium in ‘leaky’ adrenal medullary cellsFEBS Letters, 1983
- Phorbol 12-myristate 13-acetate activates rabbit neutrophils without an apparent rise in the level of intracellular free calciumBiochemical and Biophysical Research Communications, 1983
- Cytoplasmic free Ca2+ in human platelets: Ca2+ thresholds and Ca‐independent activation for shape‐change and secretionFEBS Letters, 1982
- Calcium homeostasis in intact lymphocytes: cytoplasmic free calcium monitored with a new, intracellularly trapped fluorescent indicator.The Journal of cell biology, 1982
- Modulation of brain polyphosphoinositide metabolism by ACTH-sensitive protein phosphorylationNature, 1980