Related Experiment Videos
Structural changes in platelet glycoprotein IIb/IIIa by plasmin: determinants and functional consequences
B Pasche1, H Ouimet, S Francis
1Cardiology Divisions, Brigham and Women's Hospital, Boston, MA 02115.
Blood
|January 15, 1994
Summary
Plasmin cleaves the platelet fibrinogen receptor, glycoprotein IIb/IIIa (GPIIb/IIIa), in plasma. This modification reduces fibrinogen binding and platelet aggregation, impacting blood clotting mechanisms.
Area of Science:
- Hematology
- Biochemistry
- Molecular Biology
Background:
- Plasmin is known to affect platelet aggregation.
- The direct impact of plasmin on the platelet fibrinogen receptor, glycoprotein IIb/IIIa (GPIIb/IIIa), in plasma remains unclear.
Purpose of the Study:
- To investigate the direct effect of plasmin on platelet GPIIb/IIIa in a plasma environment.
- To assess the consequences of plasmin treatment on platelet aggregation and fibrinogen binding.
Main Methods:
- Platelets were incubated with plasmin in platelet-rich plasma.
- Platelet aggregation, fibrinogen binding, and GPIIb/IIIa structural integrity were measured.
- Immunoblots and peptide sequencing were used to analyze GPIIb/IIIa cleavage.
Main Results:
- Plasmin treatment dose-dependently reduced maximal reversible fibrinogen binding and the rate of platelet aggregation.
- Plasmin cleaved GPIIIa, a subunit of GPIIb/IIIa, at the lys444-pro445 bond.
- This specific cleavage event was observed only in the presence of plasma fibrinogen.
Conclusions:
- Plasmin induces a unique proteolytic modification of GPIIb/IIIa in plasma, dependent on fibrinogen binding.
- This plasmin-mediated cleavage significantly reduces fibrinogen binding and platelet aggregation responses.