Vitronectin binds to activated human platelets and plays a role in platelet aggregation

Erica Asch, Eckhard Podack

Research output: Contribution to journalArticlepeer-review

70 Scopus citations

Abstract

Vitronectin (Vn) is a multifunctional 75-kD glycoprotein that is present in plasma and the extracellular matrix. Vn functions as a complement regulatory protein in plasma, and promotes the growth and attachment of cells in tissue culture. Recent cDNA cloning reveals that like other adhesive proteins, Vn contains the sequence Arg-Gly-Asp and binds to some members of the integrin class of adhesive membrane receptors. In liposomes, the platelet membrane glycoprotein complex IIb/IIIa binds Vn, as well as fibrinogen, von Willebrand factor, and fibronectin. We examined the binding of purified Vn to resting and stimulated human platelets. Vn bound to thrombin-stimulated platelets in a calcium-dependent, specific, and saturable manner with a Kd of 320 nM and 8,000 sites per platelet. Epinephrine or ADP stimulation led to specific binding with Kds of 93 and 116 nM, respectively. Binding was inhibited by the tetrapeptide Arg-Gly-Asp-Ser and by monoclonal and polyclonal antibodies to GPIIb/IIIa. Endogenous platelet Vn stores were identified in immunoblots of gel-filtered platelets and the surface expression of endogenous platelet Vn was thrombin inducible. Monoclonal as well as polyclonal antibodies to Vn inhibited platelet aggregation, suggesting that Vn plays a role in the formation of stable platelet aggregates.

Original languageEnglish (US)
Pages (from-to)1372-1378
Number of pages7
JournalJournal of Clinical Investigation
Volume85
Issue number5
DOIs
StatePublished - May 1990

Keywords

  • Arg-Gly-Asp
  • GPIIb/IIIa
  • Integrin
  • Receptor
  • S-protein

ASJC Scopus subject areas

  • Medicine(all)

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