ERp57 interacts with β3 integrins on mouse platelets. (A) Binding of Alexa 488-ERp57 to nonactivated (NA) and thrombin-activated (Act) wild-type (WT) mouse platelets. (B) Binding of ERp57 to nonactivated WT and β3-null platelets showing superimposable curves. (C) Binding of ERp57 to thrombin-activated WT and β3-null platelets. (D) Cumulative data for ERp57 binding to thrombin-activated platelets ± SE (n = 3). (E) Binding to Mn²⁺-treated platelets. (F) Cumulative data of ERp57 binding to Mn²⁺-treated platelets ± SE (n = 3). Washed mouse platelets (3 × 10⁸/mL) were preincubated with Alexa 488-ERp57 (30 µg/mL) for 10 minutes at 37°C and then activated by thrombin (0.3 U/mL) for 5 minutes or treated with Mn²⁺ (5 mM) for 10 minutes at 37°C. Surface binding of Alexa 488-ERp57 was detected by flow cytometry.