Model of signaling by pleckstrin leading to platelet activation. Stimulation of an agonist receptor leads to the activation of PI3K and PLC. These 2 enzymes participate in alternative signaling pathways, leading to platelet aggregation. Activation of PLC leads to the production of DAG, PKC activation, and pleckstrin phosphorylation. Once phosphorylated, pleckstrin binds to the cell membrane and contributes to integrin activation, actin assembly, and exocytosis. An alternative pathway to platelet activation involving PI3K is pleckstrin-independent.