Figure 6.

Proteins differentially expressed between GFI1B^Q287* and control platelets. Platelets from four GFI1B^Q287* patients and four healthy individuals were isolated and protein levels were assessed using mass spectrometry. Differentially expressed proteins were determined using a two-sided t-test (P<0.05 and s0=0.5). (A) Volcano plot showing the −log₁₀-transformed P-value against the log₂ fold change (FC) in relative protein levels between control and GFI1B^Q287* platelets. Dashed lines represent the statistical cutoff. A negative FC indicates proteins with reduced levels and a positive FC indicates increased levels in GFI1B^Q287* platelets. (B) Heat-map with hierarchical clustering for the 1,007 differentially expressed proteins between control and GFI1B^Q287* platelets. Heat-map colors are based on the z-scored (log₂) label-free quantification (LFQ) values. Blue shades correspond to decreased expression levels and yellow shades to increased expression levels. Imputed values are shown in case a protein was not detected. (C) Relative protein levels (log₂ LFQ values) of selected α-granule proteins in platelets of healthy controls (circles) and GFI1B^Q287* patients (squares). ANGPT1: angiopoietin-1; FGA: fibrinogen alpha chain; SPARC: secreted protein acidic and rich in cysteine; PF4: platelet factor 4; THBS1: thrombospondin-1; VWF: von Willebrand factor. (D-E) Gene ontology (GO) term enrichment analysis of the significantly expressed proteins in GFI1B^Q287* platelets. Overlap heat-maps of significant GO terms associated with downregulated (D) and upregulated (E) proteins in GFI1B^Q287* platelets. For each cluster, one or two summarizing terms are indicated. For a full list of significant GO terms see Online Supplementary Table S2.