α-granule fibrinogen and fibronectin degradation.

Western blots compare nonreduced fibrinogen (A; 5%-8% SDS-PAGE) and fibronectin (B; 4%-8% SDS-PAGE) in QPD (Q) and control (C) platelet lysates with the degradation products generated by incubating normal platelet ionophore releasate (CR) with 0, 25, 50, or 100 ng/mL tcu-PA (tcuPA), as indicated (volumes of releasate and lysates: A, 3.6 μL/lane; B, 15 μL/lane). When tcu-PA was incubated with normal platelet secretory proteins, α-granule fibrinogen and fibronectin were proteolyzed to forms that comigrated (arrows) with their degraded forms in QPD platelets.