The signal transduction induced by thrombin in human platelets.
The stimulation of human platelets by thrombin leads to the activation of phospholipases C and A2, protein kinases, formation of 3-inositol phospholipids and mobilization of Ca2+. These biochemical reactions closely parallel platelet shape change, granular secretion and aggregation. The membrane-bound transducers for the thrombin receptor seem to be the heterotrimeric G protein Gi2 and the ras-related G protein rap 1-b. Phosphorylation of rap 1-b by the action of the cyclic AMP-dependent protein kinase seems to uncouple the thrombin receptor from phospholipases. This causes inhibition of the formation of second messenger molecules and the onset of physiological responses.
Lapetina
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Cell Biology Division, Burroughs Wellcome Co., Research Triangle Park, NC 27709.
D001792:Blood Platelets / Q000378:metabolism*; D004789:Enzyme Activation; D006801:Humans; D010716:Phosphatidylinositols / Q000097:blood; D010741:Phospholipases A / Q000097:blood; D015398:Signal Transduction; D013917:Thrombin / Q000378:metabolism*; D010738:Type C Phospholipases / Q000097:blood
D010716:Phosphatidylinositols; D010741:Phospholipases A; D010738:Type C Phospholipases; D013917:Thrombin