The integrin alpha IIb/beta 3 in human platelet signal transduction

Platelets are critical for the maintenance of the integrity of the vascular system and are the first line of defence against haemorrhage. When they encounter a subendothelial matrix exposed by injury to a vessel, platelets adhere, are activated, and become adhesive for other platelets so that they a...

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Bibliographic Details
Published in:Biochemical pharmacology 2000-10, Vol.60 (8), p.1069-1074
Main Authors: Payrastre, B, Missy, K, Trumel, C, Bodin, S, Plantavid, M, Chap, H
Format: Article
Language:English
Subjects:
Animals
Antigens, CD - physiology
Blood Platelets - metabolism
Carrier Proteins - physiology
CD47 Antigen
Humans
Phosphatidylinositol 3-Kinases - physiology
Platelet Aggregation
Platelet Glycoprotein GPIIb-IIIa Complex - metabolism
Receptor, PAR-1
Receptors, Thrombin - physiology
Signal Transduction - physiology
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Summary:Platelets are critical for the maintenance of the integrity of the vascular system and are the first line of defence against haemorrhage. When they encounter a subendothelial matrix exposed by injury to a vessel, platelets adhere, are activated, and become adhesive for other platelets so that they aggregate. alpha IIb/beta 3, a platelet-specific integrin, is largely prominent amongst the adhesion receptors and is essential for platelet aggregation. The ligands for alpha IIb/beta 3 are the multivalent adhesive proteins fibrinogen and von Willebrand factor. In resting platelets, alpha IIb/beta 3 is normally in a low activation state, unable to interact with soluble fibrinogen. Stimulation of platelets with various agonists will induce a conformational change in alpha IIb/beta 3 (inside-out signalling), which is then able to bind soluble fibrinogen resulting in the onset of platelet aggregation. However, fibrinogen binding to its membrane receptor is not simply a passive event allowing the formation of intercellular bridges between platelets. Indeed, a complex signalling pathway triggered by integrin ligation and clustering (outside-in signalling) will regulate the extent of irreversible platelet aggregation and clot retraction. Amongst the signalling enzymes activated downstream of alpha IIb/beta 3 engagement, phosphoinositide 3-kinase plays an important role in the control of the irreversible phase of aggregation.
ISSN:0006-2952
DOI:10.1016/S0006-2952(00)00417-2