title: Role of the recombinant non-integrin platelet collagen receptor P65 on platelet activation induced by convulxin.
abstract: Convulxin (Cvx) isolated from Crotalus durissus terrificus venom selectively binds with a high affinity to platelets and induces platelet aggregation by a mechanism that resembles that induced by collagen. Taking advantage that P65 has been recently cloned and expressed as a recombinant soluble protein (rec-P65), we examined the role of this non-integrin collagen receptor in platelet activation induced by Cvx. Rec-P65 blocked platelet adhesion to collagen-coated surfaces and inhibited platelet aggregation and ATP secretion induced by type I collagen. On the other hand, rec-P65 did not inhibit platelet aggregation and ATP secretion induced by Cvx, and it did not affect platelet adhesion to Cvx. In addition, ligand-blotting indicated that the Cvx binding to the collagen receptor GPVI was preserved in the presence of rec-P65. These observations indicate that P65 does not play a significant role in platelet activation by Cvx; in contrast, platelet response to collagen involves multiple receptors.
authors.affiliation: Unité des Venins, Institut Pasteur, 25 rue du Dr. Roux, Paris, 75724, France. ifrancischetti@niaid.nih.gov
authors.forename: I M
authors.initials: IM
authors.lastname: Francischetti
authors.forename: T M
authors.initials: TM
authors.lastname: Chiang
authors.forename: J A
authors.initials: JA
authors.lastname: Guimarães
authors.forename: C
authors.initials: C
authors.lastname: Bon
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D003094:Collagen / Q000494:pharmacology; D003435:Crotalid Venoms / Q000494:pharmacology*; D017839:Crotalus; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D037181:Lectins, C-Type; D015539:Platelet Activation / Q000187:drug effects / Q000502:physiology*; D010973:Platelet Adhesiveness / Q000187:drug effects / Q000502:physiology; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D003435:Crotalid Venoms; D037181:Lectins, C-Type; D011994:Recombinant Proteins; C028890:convulxin; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D003094:Collagen