Figure 7. STXBP5-deficient mouse platelets have a complex granule cargo defect.

(A and B) Platelet extracts (5 × 10⁷ platelets/lane) were prepared from 3 individual Stxbp5 KO or WT mice. The indicated proteins were analyzed by IB (A) and quantified with Image Lab 4.0.1 or ImageQuant TL. After normalization using RabGDI as loading control, the Stxbp5 KO/WT ratio was calculated (B). (C) Washed platelets (2 × 10⁶) from 3 individual Stxbp5 KO or WT mice were incubated with FITC-conjugated anti-GP1bβ, anti-αIIbβ3, anti-GPVI, or anti–PECAM-1 for 15 minutes at room temperature. Geometric MFI (mean ± SEM) was determined using flow cytometry. (D) Antibody array analysis of platelet extracts. Extracts were prepared from WT or Stxbp5 KO mice and probed using duplicate Proteome Profiler Mouse Angiogenesis Antibody Arrays (see Methods). The fluorescence intensity from 2 experiments was used to calculate a Stxbp5 KO/WT ratio for each protein detected on the array. The average of the 2 calculated ratios is plotted. Note that the y axis is a log scale. SDF-1, PF4, and angiopoietin 1 were excluded from analysis due to saturation of their respective spots on the array membranes.