The p.Gly109Glu variant disrupts β1-tubulin incorporation into microtubules with a minimal effect on platelet spreading. Representative immunofluorescence analysis of β1-tubulin in patient (Pedigree I) and control washed platelets in (A) resting and (B-C) spreading conditions. Platelets were labeled with a β1-tubulin antibody (red) and with FITC-phalloidin (green). Images were acquired in a Carl Zeiss Axio Observer.A1 fluorescence microscope with a 100× objective lens. Scale bars are 5 μm. Platelet spreading on poly-l-lysine was quantified, and the percentage of totally spread platelets relative to the total adhered platelets is shown in the bar plot. Values are mean ± SD. Images were acquired in a Leica SP8 confocal microscope with a 63× objective lens (magnification, 2×). Scale bars are 20 μm. (D) Western blot pictures of β1-tubulin levels in platelet lysates from patients and controls, using 2 different β1-tubulin antibodies; β-actin was used as internal control.