Protein expression and tyrosine phosphorylation in control and GP6^homplatelets. (A) Western blot showing levels of GPVI, FcRγ, Syk, and tubulin (loading control) in control, GP6^het, and GP6^hom individuals. (B) Densitometry reading of the level of FcRγ and tubulin (loading control) in a GP6^hom individual relative to a control (the GP6^hom individual is not related to the donor in panel A). (C) Collagen (30 μg/mL) stimulation of tyrosine phosphorylation in a control and GP6^hom individual (90-second stimulation). (D) Western blot of representative proteins from GP6^het and GP6^hom donors. (E) Western blot of GPIIb from control and GP6^hom donors. Results are representative of 3 (A-C) or 4 (D-E) unrelated GP6^hom individuals. Mwt, molecular weight; WT, wild type.