Different role of platelet glycoprotein GP Ia/IIa in platelet contact and activation induced by type I and type III collagens.
The role of glycoprotein Ia/IIa was studied during platelet contact and aggregation induced by type I and type III collagen. The anti-glycoprotein Ia/IIa (6F1) antibody inhibited type I collagen-induced aggregation but did not inhibit the first contact between platelets and collagen. In contrast, it was without effect either on type III collagen-induced contact or platelet interaction with the subendothelium in a static assay. Platelet aggregation induced by type III collagen was only slightly slowed down by 6F1 but pp72 spleen tyrosine kinase phosphorylation was not modified even at concentrations of 6F1 that completely blocked platelet activation induced by type I collagen. Our results indicate that glycoprotein Ia/IIa is not a primary binding site for type I or type III collagen on the platelet membrane. This receptor is more specifically involved in type I collagen-induced platelet spreading and aggregation.
Monnet
E
E
U353 INSERM: Protéines Adhésives et Protéases des Cellules Vasculaires et Sanguines, Hôpital St. Louis, Université Paris VII-Denis Diderot- CEDEX 10, Paris, France.
Sizaret
P
P
Arbeille
B
B
Fauvel-Lafève
F
F
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001792:Blood Platelets / Q000737:chemistry* / Q000166:cytology; D003094:Collagen / Q000378:metabolism / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000378:metabolism; D006801:Humans; D016023:Integrins / Q000276:immunology / Q000502:physiology*; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D010766:Phosphorylation; D015539:Platelet Activation / Q000187:drug effects*; D010973:Platelet Adhesiveness; D010974:Platelet Aggregation / Q000187:drug effects; D038981:Receptors, Collagen; D014443:Tyrosine / Q000378:metabolism
D000911:Antibodies, Monoclonal; D016023:Integrins; D038981:Receptors, Collagen; D014443:Tyrosine; D003094:Collagen