LIMK1 stimulates platelet aggregation and secretion induced by VWF. (A) Immunoblots of platelet lysates from WT and LIMK1-knockout mice probed with an anti-LIMK1 antibody and an anti-β3 integrin antibody (loading control). (B) Aggregation and adenosine triphosphate (ATP) secretion traces of WT and LIMK1^−/− platelets stimulated with VWF (15 μg/mL) and the indicated doses of botrocetin. (C) Flow cytometric analysis of the binding of VWF to WT and LIMK1^−/− platelets. (D) Quantitation of WT or LIMK1^−/− platelet adhesion to VWF-coated microtiter wells in the presence of botrocetin using an acid phosphatase assay. (E-H), Aggregation of WT and LIMK1^−/− platelets in response to: collagen (E), PAR4AP (F), U46619 (G), and ADP and fibrinogen (H).