Piceatannol inhibition of protein tyrosine phosphorylation in platelets. Human platelets were pretreated with DMSO or piceatannol (40 μg/mL) for 10 minutes at room temperature before the addition of PBS (−), 0.1 U/mL thrombin, or 0.1 U/mL thrombin plus stirring. After 2 minutes, the platelets were solubilized in RIPA buffer and the proteins were separated by SDS-PAGE on an 8% gel and transferred to nitrocellulose. (A) Total protein lysates. (B) FAK immunoprecipitated from platelet lysates. In each case the blots were probed with the antiphosphotyrosine antibodies 4G10 and PY-20. (B) The blot stripped and reprobed with the anti-FAK antibody to confirm equal loading of protein. Proteins were visualized using ECL detection methods. The molecular weight standards are indicated to the left.