title: [Study on conformational changes of GP IIb/IIIa complex during platelet activation].
abstract: OBJECTIVE
  To determine whether a conformational change in GPIIb/IIIa occurs during platelet activation.
  
  
  METHODS
  Epitopes on GPIIb/IIIa complex were labeled with McAbs to GPIIb (SZ-22) and GPIIIa (SZ-21) conjugated to either a donor fluorescein (FITC-labeled) or an acceptor (TR-labeled) chromophore. The FRET between platelet-bound FITC and TR was measured and calculated by flow cytometry during platelet activation induced by some agonists.
  
  
  RESULTS
  In unstimulated platelets, a small but consistent change of FRET (5.5%) was detected, regardless of which antibody served as FRET donor. Platelet activation resulted in an obvious increase in FRET, suggesting a significant change in the separation or orientation of the epitopes within GPIIb/IIIa. This kind of changes could also occur on removing the extracellular calcium, and was independent of receptor occupancy.
  
  
  CONCLUSIONS
  The increase in FRET can reflect the rearrangement of the chromophore-labeled McAbs bound to GPIIb/IIIa during platelet activation, and this kind of structural rearrangement subunits of GPIIb/IIIa complex subunits can induce fibrinogen receptor expression.
authors.affiliation: Institute of Hematology, CAMS and PUMC, Tianjin 300020.
authors.forename: L
authors.initials: L
authors.lastname: Peng
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: H
authors.initials: H
authors.lastname: Wu
mesh_terms: D005434:Flow Cytometry; D006801:Humans; D015539:Platelet Activation; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D019039:Platelet Glycoprotein GPIIb-IIIa Complex