TPO-induced Akt phosphorylation. Purified platelets from hTg^WT and hTg^Y605X were stimulated with TPO (200 ng/mL) for the indicated times. Platelet lysates were subjected to Western blot analysis using either an antiphospho-Akt (Ser473) antibody (A) or an antiphosphotyrosine polyclonal antibody (B). The upper blot was reprobed using an anti-Akt polyclonal antibody to visualize protein loads and is shown for comparison (middle panel).