Myosin binds to VWF. VWF:Ag is shown for plasma-derived VWF and recombinant VWF. (A) Myosin binding in plasma samples from healthy donors (“control”) and donors with VWF (types 3, 1, and 2A). No significant difference was found between the control myosin binding and type 1 myosin binding, but control myosin binding and type 1 myosin binding were significantly different compared with type 2 myosin binding. (B) Myosin binding is dependent on presence of high molecular weight multimers using recombinant VWF separated into fractions based on the molecular weight of the multimers contained therein (ultra high, high, medium, and low). A significant difference was noted for the medium and low molecular weight multimers compared with the high and ultrahigh molecular weight multimers. (C) Myosin binding to recombinant VWF, including WT recombinant VWF, constructs containing VWF variants that affect multimerization (87S and 2773R), the VWF A3 domain (1786D), which affects collagen III binding, a C-terminal domain RGD site variant (2509E), a D′ variant causing type 2N VWD (791M), and a construct without any VWF sequence as a negative control (mock). (D) A1 domain specificity of myosin binding to recombinant VWF constructs. n ≥ 3. Error bars denote 1 standard deviation. *P < .05, **P < .005.