Direct relationship between intracellular calcium mobilization and phospholipase D activation in prostaglandin E-stimulated human erythroleukemia cells.
Biochemistry
; 31(13): 3370-7, 1992 Apr 07.
Article
em En
| MEDLINE
| ID: mdl-1313295
ABSTRACT
The relationship between calcium mobilization and phospholipase D (PLD) activation in response to E-series prostaglandins (PGEs) was investigated in human erythroleukemia cells. Intracellular free Ca2+ concentration ([Ca2+]i) was increased by PGE1 and PGE2 over the same concentration range at which PLD activation was seen. Pretreatment of cells with pertussis toxin greatly inhibited the PGE-stimulated increase in [Ca2+]i, implying that a G protein participates in the PGE receptor signaling process. The peak level and also the plateau level of Ca2+ mobilization stimulated by these prostaglandins were markedly decreased in Ca(2+)-depleted medium, indicating that both extracellular and intracellular Ca2+ stores contribute to the changes in [Ca2+]i. Likewise, activation of PLD by PGE1 and PGE2 was abolished by pertussis toxin pretreatment or incubation in Ca(2+)-depleted medium. U73122, a putative phospholipase C inhibitor, blocked both Ca2+ mobilization and PLD activation in PGE-stimulated cells. Furthermore, the intracellular loading of BAPTA, a Ca2+ chelator, inhibited both Ca2+ mobilization and PLD activation by PGE1 and PGE2 in a similar dose-dependent manner. Simultaneous measurement of [Ca2+]i and PLD activity in the same cell samples indicated that PLD activity increases as a function of [Ca2+]i in a similar fashion in cells stimulated either by PGEs or by the calcium ionophore ionomycin. Taken together, these findings suggest that a rise in [Ca2+]i is necessary for PGE-stimulated PLD activity in human erythroleukemia cells.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfolipase D
/
Prostaglandinas E
/
Leucemia Eritroblástica Aguda
/
Cálcio
Limite:
Humans
Idioma:
En
Revista:
Biochemistry
Ano de publicação:
1992
Tipo de documento:
Article