PMID: 7542872Jul 15, 1995Paper

Regulation of platelet glycoprotein IIb/IIIa (integrin alpha IIB beta 3) function via the thrombin receptor

The Biochemical Journal
A N GiesbertsJ W Akkerman

Abstract

Binding sites on glycoprotein (GP) IIb/IIIa exposed by 0.5 unit/ml alpha-thrombin are insensitive to prostaglandin I2 (PGI2), in contrast with sites exposed by ADP or platelet-activating factor. Here we show that the thrombin receptor agonist peptide (TRAP) (SFLLRN; 15 microM) opens almost the same number of GPIIb/IIIa molecules as 0.5 unit/ml alpha-thrombin (64840 +/- 8920 compared with 81050 +/- 6030 molecules of fibronectin bound/platelet), but these sites rapidly close on addition of PGI2. To investigate whether alpha-thrombin and TRAP initiate different signalling pathways, we measured phospholipase C (PLC)-mediated control of GPIIb/IIIa and its sensitivity to cyclic AMP. Optimal concentrations of alpha-thrombin and TRAP activated PLC maximally, but TRAP induced only about 50% protein kinase C PKC) activation after 10 min stimulation compared with alpha-thrombin. These concentrations also suppressed PGI2-induced cyclic AMP accumulation, with alpha-thrombin inducing complete inhibition and TRAP about 10% less. Direct activation of PKC by phorbol 12-myristate 13-acetate confirmed earlier observations that PGI2-induced cyclic AMP accumulation is partly inhibited via PKC. Applying different concentration of alpha-thrombin, TRA...Continue Reading

Citations

Nov 5, 1997·Arteriosclerosis, Thrombosis, and Vascular Biology·H van der VuurstJ W Akkerman
Nov 19, 2005·Pathophysiology of Haemostasis and Thrombosis·Frank GerdsenEdelgard Lindhoff-Last
Mar 6, 2009·The Journal of Biological Chemistry·Roger W HunterIngeborg Hers
Sep 27, 2000·Hematology/oncology Clinics of North America·F A Ofosu, K A Nyarko
Jul 16, 2008·Vascular Pharmacology·Arata Tabuchi, Wolfgang M Kuebler

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