Linked Life Data

1505199

Source:http://linkedlifedata.com/resource/pubmed/id/1505199

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1992-9-21
pubmed:abstractText
This study was performed to determine the effects of phorbol esters and ionomycin on phospholipase D (PLD) activity in bovine corneal epithelial cells (BCEC). The cells were prelabeled with [3H]myristic acid and incubated for specific time intervals with various test agents in the presence and absence of ethanol. The PLD activity was assayed by monitoring the formation of labeled phosphatidylethanol ([3H]PEt) in [3H]myristate labeled cells. In the absence of ethanol, 1 microM phorbol 12-myristate 13-acetate (PMA) increased the formation of labeled phosphatidic acid ([3H]PA) with no significant effect on the radioactivity of [3H]PEt. In the presence of 85 mM ethanol, whereas there was only a small further increase in [3H]PA, the formation of [3H]PEt was increased by several-fold, demonstrating activation of PLD by the phorbol ester. The effects of PMA were time- and dose-dependent, and were mimicked by phorbol 12,13-dibutyrate. The inactive phorbol derivatives, 4-alpha-phorbol, 4-alpha-phorbol 12,13-didecanoate, 4-alpha-phorbol 12-myristate 13-acetate and 4-alpha-phorbol 12,13-dibutyrate, were without effect. Short-time (30 min) incubation of BCEC with staurosporine or H-7, or prolonged (20 hours) incubation with PMA rendered the cells less sensitive to subsequent treatment with PMA, suggesting that activation of PLD in the cells is mediated by protein kinase C (PKC). Addition of 20 microM ionomycin in the presence of ethanol also increased the formation of [3H]PA and [3H]PEt in a time- and dose-dependent manner. Co-presence of ionomycin and PMA at submaximal concentrations in the incubation medium resulted in increased formation of [3H]PA and [3H]PEt which was less than their individual effects combined, indicating a lack of synergism between Ca2+ and PMA in activating PLD. Incubation of BCEC with staurosporine resulted in significant inhibition of ionomycin-induced production of [3H]PEt, suggesting that in addition to direct activation of PLD by Ca2+, the enzyme is probably stimulated by sequential activation of PLC (producing diacylglycerol) and PKC following the ionomycin addition. We conclude that BCEC possess PLD which is stimulated by PKC as well as elevated intracellular Ca2+.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Ethanol, http://linkedlifedata.com/resource/pubmed/chemical/Glycerophospholipids, http://linkedlifedata.com/resource/pubmed/chemical/Ionomycin, http://linkedlifedata.com/resource/pubmed/chemical/Myristic Acid, http://linkedlifedata.com/resource/pubmed/chemical/Myristic Acids, http://linkedlifedata.com/resource/pubmed/chemical/Phorbol Esters, http://linkedlifedata.com/resource/pubmed/chemical/Phosphatidic Acids, http://linkedlifedata.com/resource/pubmed/chemical/Phospholipase D, http://linkedlifedata.com/resource/pubmed/chemical/Phospholipids, http://linkedlifedata.com/resource/pubmed/chemical/Protein Kinase C, http://linkedlifedata.com/resource/pubmed/chemical/Protein Kinase Inhibitors, http://linkedlifedata.com/resource/pubmed/chemical/phosphatidylethanol
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0271-3683
pubmed:author
pubmed:issnType
Print
pubmed:volume
11
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
553-64
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Stimulation of phospholipase D by phorbol esters and ionomycin in bovine corneal epithelial cells.
pubmed:affiliation
Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912-2100.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.