Fig. 3: GPIb-IX expression is reduced in Zyx^-/- platelets and MKs.

A Differential proteomic analysis of proteins expressed in WT and Zyx^−/− platelets; n = 3 mice per genotype. B Surface level of GPIb-IX complex on WT and Zyx^−/− platelets analyzed by flow cytometry; n = 3 mice per genotype. MFI, mean fluorescence intensity. C Western blot analysis of GPIb-IX in WT and Zyx^−/− platelets. Protein concentration has been adjusted to the same level between WT and Zyx^−/− platelet lysates. Blots are representative of five independent experiments. D Expression of GPIb-IX complex in WT and Zyx^−/− MKs. Left panels, representative confocal images of MKs in WT and Zyx^−/− mouse femoral BM sections immunostained with anti-GPIbα, GPIbβ, and GPIX antibodies (original magnification ×200). GPIbα, GPIbβ, and GPIX in MKs are in green, and nuclei are in blue. Scale bar: 100 μm. Right panels, the quantification of MFI of GPIbα, GPIbβ, and GPIX in the left panels analyzed by ImageJ software; n = 10 visual fields from 5 mice per genotype. Data are expressed as means ± SD. E Percentage of GPIbα⁺ cells differentiated from WT and Zyx^−/− FL HPCs was analyzed by flow cytometry. F Percentage of GPIbα⁺ platelet-sized particles released from culture-derived MKs in (E) was analyzed by flow cytometry. Data are from four independent experiments in (E) and (F). Means are indicated by horizontal lines in (A), (B), (E), and (F). **P < 0.01, ***P < 0.001, compared with WT mice by unpaired Student’s t-test in (A), (B), and (D), and by two-way ANOVA followed by Bonferroni’s post hoc test in (E) and (F).