title: Evidence for two functionally different fibrinogen receptors on hemopoietic cells: the glycoprotein IIb-IIIa and the mitogenic fibrinogen receptor.
abstract: We have previously established that the mitogenic effect of fibrinogen on hemopoietic cell lines Raji and JM is mediated via a specific receptor (Levesque, J.-P. et al.: Proc. Natl. Acad. Sci. USA 83:6494-6498, 1986). In this study, we have further characterized the fibrinogen domain involved in the binding to the mitogenic receptor. This binding was not inhibited either by a monoclonal antibody against the C-terminal sequence of the fibrinogen gamma chains or by synthetic peptides containing the Arg-Gly-Asp sequence. Such inhibition is specific of the platelet fibrinogen receptor, the glycoprotein IIb-IIIa complex. Fragments containing the fibrinogen D domain were the only plasmin degradation products of fibrinogen which were mitogenic. These fragments acted via direct binding on the mitogenic receptor with a Kd of 2.24 X 10(-6) M. This value was similar to the KI value of unlabeled fragments D (2.47 X 10(-6) M). Our results suggest the presence of two different functional types of fibrinogen receptors: the glycoprotein IIb-IIIa receptor responsible both for platelet aggregation and leukocyte adhesion and killing, and the mitogenic receptor involved in proliferation control of hemopoietic cells.
mesh_terms: D000911:Antibodies, Monoclonal; D001667:Binding, Competitive; D001792:Blood Platelets / Q000378:metabolism; D002460:Cell Line; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism / Q000494:pharmacology; D005340:Fibrinogen / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D007457:Iodine Radioisotopes; D008938:Mitosis; D009842:Oligopeptides / Q000494:pharmacology; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D005338:Fibrin Fibrinogen Degradation Products; D007457:Iodine Radioisotopes; D009842:Oligopeptides; D010980:Platelet Membrane Glycoproteins; C027539:fibrinopeptides gamma; D005340:Fibrinogen