Localization of WASP in normal MKs after adhesion on Poly-L-lysine. Examination of normal MKs was performed as described in Fig 5. MKs were labeled with anti-vWF polyclonal antibody (AMCA), phalloidin (FITC), and anti-WASP MoAb (TRITC) after 30 minutes of adhesion to poly-L-lysine–coated coverslips. Anti-vWF labeling (AMCA) allowed the localization of MKs. Unlike vWF, WASP is localized in filopodia (A) with the same topography as F-actin (B).