Platelet-derived ERp57 is required for hemostasis, thrombosis, and platelet accumulation into a growing thrombus. (A) Tail bleeding times and (B) time to occlusion of FeCl₃-induced carotid artery thrombosis in Pf4-Cre/ERp57^fl/fl mice compared with ERp57^fl/fl littermate controls. (C) Incorporation of platelets from ERp57^fl/fl or Pf4-Cre/ERp57^fl/fl mice into the growing thrombus. (D) Composite of FI/µm² in ERp57^fl/fl, • (n = 18) and Pf4-Cre/ERp57^fl/fl, ■ (n = 16) mice ± SE; *P < .05. Mean vessel diameters; ERp57^fl/fl 114.8 ± 5.7; Pf4-Cre/ERp57^fl/fl: 111.1 ± 5.4 (P = NS). Dotted lines mark the vessel wall. White bar = 100 µm. Images are ×100 magnification.