Fibrinogen fragment D is a recognition site for release-related platelet aggregation.
The present study probes for the segment of the fibrinogen molecule which interacts with the platelet surface upon induction of release-related aggregation. The capability of platelets affixed with fibrinogen fragment D or fibrinogen fragment E to enhance aggregation of gel-filtered platelets (GFP) was compared with that of platelets affixed with fibrinogen. It is shown that release-related aggregation induced by either A23187, 10 microM ADP or thrombin is enhanced by the addition of fixed platelets bearing covalently bound fragment D by as much as 60-70% of the augmentation obtained by platelets bearing fibrinogen. On the other hand, fixed platelets bearing covalently-bound fragment E have no effect on the aggregation of GFP. It is concluded that fragment D bears the site for the interaction of fibrinogen with activated platelets, apparently, with surface-bound thrombospondin.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D001665:Binding Sites; D001792:Blood Platelets / Q000502:physiology; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D005340:Fibrinogen / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D010974:Platelet Aggregation / Q000187:drug effects; D013917:Thrombin / Q000494:pharmacology; D019699:Thrombospondins
D005338:Fibrin Fibrinogen Degradation Products; D006023:Glycoproteins; D019699:Thrombospondins; C015214:fibrinogen D fragment; D000244:Adenosine Diphosphate; D005340:Fibrinogen; D013917:Thrombin