Pathophysiology of platelet thrombin receptors.
The evidence is reviewed and a model presented for two distinct receptors being involved in platelet activation induced by alpha-thrombin: a high affinity thrombin receptor constituting approximately 50 copies of a supercomplexed form of GPIb coupled to phospholipase A2 and a moderate affinity receptor constituting approximately 2000 copies of the proteolytically activated, G protein-coupled seven transmembrane domain receptor coupled to phospholipase C. Reasons for the failure of certain studies to detect this role for GPIb are discussed.
Jamieson
G A
GA
American Red Cross, Rockville, MD 20855, USA. Jamieson@USA.redcross.org
D001791:Blood Platelet Disorders / Q000503:physiopathology*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006801:Humans; D015539:Platelet Activation; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000378:metabolism / Q000502:physiology*; D018179:Receptors, Thrombin / Q000502:physiology*
D019038:Platelet Glycoprotein GPIb-IX Complex; D011956:Receptors, Cell Surface; D018179:Receptors, Thrombin; D019204:GTP-Binding Proteins