Reduced platelet adhesion and aggregate formation onto injured vessel walls of β1-null, β1^TTAA, and β1^hpmmice, whereas tail bleeding times of β1^hpmmice are normal. (A) Number of adherent fluorescently labeled platelets to the injured vessel wall was quantified after 5, 10, 15, and 60 minutes. Values are expressed as percentage of adherent wild-type (WT) platelets (n/mm²) at 5 minutes (WT, n = 9; HT, n = 6; knockout [KO], n = 6; TTAA, n = 4; Hpm, n = 8; bars represent mean values ± SEM in percent, significance level are indicated; *P < .05; **P < .01 by one-way analysis of variance followed by a Tukey multiple comparison test). (B) Tail-bleeding times of chimeric mice carrying the bone marrow of the indicated genotype (WT, n = 19; fl/fl, n = 6; HT, n = 10; KO, n = 9; TTAA, n = 15; TTAA/fl, n = 6; Hpm, n = 13; Hpm/fl, n = 6; Kindlin-3^−/−, n = 4; cross line represents mean bleeding time and bars represent SEM, significance level are indicated; **P < .01).