Platelet receptors.
This article highlights the increasing knowledge of the biochemistry, pathology, and cell and molecular biology of platelet receptors. A receptor for ADP has been identified using the affinity label FSBA as aggregin, a 100-kd membrane protein, responsible for shape change, aggregation, and exposure of fibrinogen binding sites. A variety of putative receptors for collagen have been described with GP Ia and GP IV receiving the most attention recently. A thromboxane A2 receptor has been identified using receptor antagonists and photoaffinity labels. The alpha 2-adrenergic receptor has been cloned and expressed. The platelet thrombin receptor has been identified as GP Ib. Following binding of thrombin to this receptor, activation of calpain occurs with cleavage of aggregin leading to exposure of GP IIb/IIIa and platelet aggregation. Isolation, expression, or both of the ADP, collagen, and thrombin receptors as single gene products of the human platelet responsible for activation, and more complete understanding of stimulus-response coupling should allow for greater specificity of drugs with selective therapeutic actions.
Colman
R W
RW
Thrombosis Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania.
D000244:Adenosine Diphosphate / Q000502:physiology; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D003094:Collagen / Q000502:physiology; D006801:Humans; D015539:Platelet Activation / Q000187:drug effects; D010980:Platelet Membrane Glycoproteins / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000502:physiology*; D013917:Thrombin / Q000502:physiology; D013928:Thromboxane A2 / Q000502:physiology
D010980:Platelet Membrane Glycoproteins; D011942:Receptors, Adrenergic, alpha; D011956:Receptors, Cell Surface; D013928:Thromboxane A2; D000244:Adenosine Diphosphate; D003094:Collagen; D013917:Thrombin