Detection of Nox1 protein in magnetic bead–purified MKs. (A) Example of enrichment of CD41-FITC–labeled MKs after purification of TPO-stimulated BM cultures as described in “Methods.” Purity was assessed by fluorescence microscopy. Images are shown at ×400 magnification. (B) BM was isolated and cultured for 3 days (+TPO) before magnetic bead purification. Western blots were probed with antibodies for CD41, Nox1, and β-actin.