Selective Mylk inhibition by ML7 affects proplatelet formation and stabilization and interferes with platelet Clec-2 and GPVI downstream signaling. (A) Graphic representation of Mylk gene, Mylk isoform 3, and the peptide coverage identified in dKO platelets corresponding to Mylk isoform 3. Sp GC-rich binding sites are depicted on the promoter region upstream the Mylk isoform 3 ATG starting codon. (B) Explant assay performed with WT mice after addition of Mylk inhibitor ML7 at different concentrations or DMSO. The percentage of megakaryocytes with proplatelets of total counted megakaryocytes per explant is depicted. See supplemental Videos 4-7 showing that ML7 inhibition of Mylk after proplatelet formation results in proplatelet retraction. (C) FCA of WT platelets preincubated with either DMSO or ML7. *P < .05; ***P < .001.