Twf2a is a critical regulator of platelet reactivity in vivo. (A-B) Accelerated adhesion of platelets (A) and occlusion of mesenteric arterioles (B) in Twf2a^−/− mice upon FeCl₃-induced injury of the endothelial barrier. Each symbol represents 1 mesenteric arteriole (n = 12 individuals). (C) Accelerated hemostatic plug formation in Twf2a^−/− mice. Each symbol represents 1 individual (n = 10 individuals). Horizontal lines represent mean. ***P < .001 and **P < .01, Wilcoxon-Mann-Whitney test (A-B) and unpaired Student t test (C).