Lysophosphatidic acid induces protein tyrosine phosphorylation in the absence of phospholipase C activation in human platelets

M. Torti, E. Tolnai Festetics, A. Bertoni, R. Moratti, C. Balduini, F. Sinigaglia

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Lysophosphatidic acid is a biologically active phospholipid able to induce cell proliferation and platelet aggregation. In this study we investigated the biochemical mechanisms of platelet activation by lysophosphatidic acid. We found that lysophosphatidic acid stimulated the binding of the photoreactive GTP-analog 4-azidoanilido-[α32P]GTP to a 40-kDa protein on platelet membranes. Moreover, lysophosphatidic acid induced the rapid decrease of the intracellular concentration of cAMP in intact platelets, indicating that this lipid activates platelets by binding to a membrane receptor coupled to the inhibitory GTP-binding protein Gi. In agreement with a receptor-mediated action, we found that platelet activation by lysophosphatidic acid underwent homologous desensitization. In the absence of extracellular CaCl2, lysophosphatidic acid did not induce platelet aggregation, and did not stimulate phospholipase C. However, under the same conditions, lysophosphatidic acid produced the rapid tyrosine phosphorylation of several platelet proteins. This effect was not mediated by the formation of thromboxane A2. Our results demonstrate that, in lysophosphatidic acid-stimulated platelets, activation of protein-tyrosine kinases occurs in the absence of phospholipase C activation and platelet aggregation, and may be directly related to the activation of the G-protein-coupled lysophosphatidic acid-receptor.

Original languageEnglish
Pages (from-to)181-187
Number of pages7
JournalPlatelets
Volume8
Issue number2-3
DOIs
Publication statusPublished - 1997

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Type C Phospholipases
Tyrosine
Blood Platelets
Phosphorylation
Platelet Activation
Proteins
Platelet Aggregation
Guanosine Triphosphate
GTP-Binding Proteins
Lysophosphatidic Acid Receptors
Cell Aggregation
Thromboxane A2
Membranes
lysophosphatidic acid
Protein-Tyrosine Kinases
Phospholipids
Cell Proliferation
Lipids

ASJC Scopus subject areas

  • Hematology
  • Cell Biology

Cite this

Lysophosphatidic acid induces protein tyrosine phosphorylation in the absence of phospholipase C activation in human platelets. / Torti, M.; Festetics, E. Tolnai; Bertoni, A.; Moratti, R.; Balduini, C.; Sinigaglia, F.

In: Platelets, Vol. 8, No. 2-3, 1997, p. 181-187.

Research output: Contribution to journalArticle

Torti, M, Festetics, ET, Bertoni, A, Moratti, R, Balduini, C & Sinigaglia, F 1997, 'Lysophosphatidic acid induces protein tyrosine phosphorylation in the absence of phospholipase C activation in human platelets', Platelets, vol. 8, no. 2-3, pp. 181-187. https://doi.org/10.1080/09537109777456
Torti, M. ; Festetics, E. Tolnai ; Bertoni, A. ; Moratti, R. ; Balduini, C. ; Sinigaglia, F. / Lysophosphatidic acid induces protein tyrosine phosphorylation in the absence of phospholipase C activation in human platelets. In: Platelets. 1997 ; Vol. 8, No. 2-3. pp. 181-187.
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