Involvement of platelet glycoprotein IIb-IIIa (alpha IIb-beta 3 integrin) in thrombin-induced synthesis of phosphatidylinositol 3',4'-bisphosphate.

Abstract

32P-Labeled human platelets were incubated with thrombin (1 unit/ml) for 5 min at 37 degrees C under conditions allowing maximal synthesis of [32P]phosphatidylinositol 3',4'-bisphosphate (PtdIns(3,4)P2). Incorporation of 32P into the latter phosphoinositide was dose-dependently reduced (to a maximal level averaging 60%) by the tetrapeptide RGDS, an inhibitor of fibrinogen binding to activated glycoprotein IIb-IIIa (alpha IIb-beta 3 integrin). Identical results were obtained with the fibrinogen gamma-chain dodecapeptide HHLGGAKQAGDV, whereas the tripeptide RGD and the tetrapeptide RGES displayed reduced or undetectable effects on 32P labeling of PtdIns(3,4)P2, respectively, in good correlation with their ability to inhibit platelet aggregation and fibrinogen binding to activated alpha IIb-beta 3 integrin. In addition, pathological platelets from three patients suffering thrombasthenia, which lack alpha IIb-beta 3 integrin and fail to aggregate in response to thrombin, displayed hardly detectable increases in the 32P labeling of PtdIns(3,4)P2. In contrast, thrombin-stimulated synthesis of PtdIns(3,4)P2 was unaltered in other deficient platelets lacking the glycoprotein Ib-IX complex (Bernard-Soulier syndrome). Although additional pathways seem to be involved in the regulation of phosphatidylinositol-3-kinase, these data indicate a strong relationship between platelet aggregation involving fibrinogen binding to activated alpha IIb-beta 3 integrin and the synthesis of the novel phosphoinositides phosphorylated at position D-3 of the inositol ring.

• Authors: C Sultan, M Plantavid, C Bachelot, P Grondin, M Breton, G Mauco, S Lévy-Toledano, J P Caen, H Chap
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 266 Issue 35 Pg. 23554-7 (Dec 15 1991) ISSN: 0021-9258 [Print] United States
• PMID: 1660876 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Oligopeptides
• Phosphatidylinositol Phosphates
• Phosphatidylinositols
• Phospholipids
• Platelet Membrane Glycoproteins
• phosphatidylinositol 3,4-diphosphate
• Fibrinogen
• Thrombin

Topics

• Amino Acid Sequence
• Blood Platelets (drug effects, metabolism)
• Chromatography, High Pressure Liquid
• Fibrinogen (metabolism)
• Humans
• Kinetics
• Molecular Sequence Data
• Oligopeptides (chemical synthesis, pharmacology)
• Phosphatidylinositol Phosphates
• Phosphatidylinositols (biosynthesis, blood, isolation & purification)
• Phospholipids (biosynthesis, blood, isolation & purification)
• Platelet Membrane Glycoproteins (physiology)
• Reference Values
• Thrombasthenia (blood)
• Thrombin (metabolism)