Interaction of the A1A2A3 proteins with vimentin. (A) WT-A1A2A3 protein or gain-of-function A1A2A3 mutant (250 nmol/L) was incubated with immobilized vimentin in the absence of ristocetin. The bound protein was determined by ELISA, using the antibody against human VWF as described in “Methods.” Bars represents the mean ± SD of values obtained from 3 determinations, ^#P < .01. (B) ADP-stimulated (20 μM) washed platelets were incubated with anti-vimentin antibody, V9, or mouse IgG (25 μg/mL), followed by the addition of the mutant A1A2A3 (250 nmol/L). Mouse IgG without the A1A2A3 mutant was used as negative control and is represented by the dark solid line. The V9 decreases the interaction of the mutant A1A2A3 with platelets by an average of 45% (dotted line), based on mean fluorescence intensities (MFIs). The data represent 2 separate experiments.