Gp-regulated phosphoinositide hydrolysis in turkey and human erythrocytes exposed to fluoride ion

Relationship to calcium influx

Denis English, Luke P. Akard, Gregory S. Taylor, Maria Teresa Rizzo, Jesus Dominguez, Joe G N Garcia

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Previous studies have demonstrated that although both mammalian and avion erythrocytes express an inducibie inositol bisphosphate-specific phospholipase C, only the latter possess the guanine nucleotide-binding protein (Gp) that regulates this activity. In confirmation of previous reports, turkey erythrocyte plasma membranes responded to guanosine 5′-0-(3-thio)triphosphcrte (GTP-γ-S) and fluoroaluminates with hydrolysis of phosphoinositides, release of inositol phosphates, and generation of diacylglycerol, whereas human erythrocyte plasma membranes exhibited no such changes when incubated with known activators of guanine nucleotide regulatory proteins. We next contrasted responses of intact turkey and human erythrocytes to fluoroaluminates to develop a model to investigate the cellular effects of Gp activation. When turkey erythrocytes were exposed to fluoroaluminates, cellular levels of diacylglycerol and phosphatidic acid rapidly increased as phosphoinosirides were hydrolyzed. The alterations in the lipid composition of turkey erythrocytes effected by fluoroaluminates were remarkable; phosphatidic acid levels increased over 30-fold, whereas levels of polyphosphoinositides were decreased to less than 10% of those present before stimulation. In contrast, fluoroaluminates caused only minor alterations in the diacylglycerol and phospholipid content of intact human erythrocytes. To define the role of inositol-specific phospholipase C activation in the transmembrane conveyance of extracellular Ca++, we compared the influx of extracellular Ca++ in human and turkey erythrocytes exposed to fluoroaluminates. Fluoroaluminates initiated a sustained influx of extracellular 45Ca++ into turkey, but not human, erythrocytes. These results provide strong support for the hypothesis that Gp activation results in an influx of calcium into stimulated cells. Moreover, the data demonstrate that comparison of responses of human and turkey erythrocytes to fluoroaluminates provides a well-defined method for investigating the mechanisms and consequences of Gp activation in intact cells.

Original languageEnglish
Pages (from-to)87-98
Number of pages12
JournalJournal of Laboratory and Clinical Medicine
Volume119
Issue number1
StatePublished - 1992

Fingerprint

Phosphatidylinositols
Fluorides
Hydrolysis
Diglycerides
Erythrocytes
Chemical activation
Ions
Calcium
Phosphatidic Acids
Type C Phospholipases
Inositol
Cell membranes
Phosphatidylinositol Phosphates
Inositol Phosphates
Guanine Nucleotides
Guanosine
Erythrocyte Membrane
Guanosine Triphosphate
GTP-Binding Proteins
Phospholipids

ASJC Scopus subject areas

  • Medicine(all)
  • Pathology and Forensic Medicine

Cite this

Gp-regulated phosphoinositide hydrolysis in turkey and human erythrocytes exposed to fluoride ion : Relationship to calcium influx. / English, Denis; Akard, Luke P.; Taylor, Gregory S.; Rizzo, Maria Teresa; Dominguez, Jesus; Garcia, Joe G N.

In: Journal of Laboratory and Clinical Medicine, Vol. 119, No. 1, 1992, p. 87-98.

Research output: Contribution to journalArticle

English, Denis ; Akard, Luke P. ; Taylor, Gregory S. ; Rizzo, Maria Teresa ; Dominguez, Jesus ; Garcia, Joe G N. / Gp-regulated phosphoinositide hydrolysis in turkey and human erythrocytes exposed to fluoride ion : Relationship to calcium influx. In: Journal of Laboratory and Clinical Medicine. 1992 ; Vol. 119, No. 1. pp. 87-98.
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