Actin-binding ability of the protein with the molecular weight of 47,000 phosphorylated during platelet activation

The platelet protein, P47, with the molecular weight of 47,000 that is phosphorylated during platelet activation is closely associated with secretion from granules in these cells. P47 interacts with actin directly or indirectly. We investigated the ability of P47 to bind to actin by actin-affinity chromatography. In the eluate from an actin-Sepharose column, there was no phosphorylated P47, but in the first fraction that passed through the column, there was. The results suggested that P47 does not bind to actin directly.