ADP and TxA2 enhance Akt phosphorylation.

EDTA treatment of wild-type platelets inhibited aggregation induced by a medium concentration of γ-thrombin. In the absence of aggregation, platelets were also activated with 5 μM ADP or 0.05 μM U46619, or both, in the presence of a medium concentration of γ-thrombin. Akt phosphorylation was restored by the addition of ADP and U46619 in the γ-thrombin–stimulated platelets in the absence of aggregation. Thus, aggregation is not absolutely required for Akt phosphorylation.