MPαC activates PKC in platelets. (A) Volcano plot showing the distribution of the significance and fold change of identified phosphopeptides between MPαC- and MPαCsc-treated human platelets (n = 3). Red and blue dots indicate the significantly increased (351) and decreased (818) phosphopeptides in MPαC- vs MPαCsc-treated samples (fold change >1.2 or <0.83; P < .05 by 2-tailed Student t test). (B) Kinases predicted to be activated and inhibited. The x-axis represents the score of kinase activity, and the y-axis represents the kinases predicted to be significantly regulated (P < .05). Red represents the activation status, and blue represents the inhibition status. (C) Representative blot of MPαC-induced PKC substrate (pleckstrin) phosphorylation in washed human platelets and quantification of the densitometry in the blots (n = 5 independent experiments). One-way ANOVA followed by Dunnett post hoc test (compared with vehicle control dimethyl sulfoxide [DMSO]) in panel C. Data are shown as mean ± SEM for panel C. ∗P < .05 and ∗∗∗P < .001.