OBJECTIVE

To investigate the expression of mDia1 (mammalian diaphanous 1)in platelet and the role of mDia1 or phosphatidylinositol 3-kinase (PI3K) in the process of thrombin-induced platelet aggregation.

METHODS

The extent of platelet aggregation was measured by a platelet aggregation system and the expression of mDia1 and its relation with F-actin in quiescent, spreading or aggregated platelets by Western blot.

RESULTS

There was no significant difference in mDia1 expression level between quiescent and activated platelets. mDia1 moved from a Triton-X100-soluble cytosolic fraction to insoluble cytoskeleton fraction after thrombin induced platelets aggregation. Anti-mDia1 antibody could inhibit this aggregation. PI3K inhibitor Wortmannin or Ly294002 inhibited the thrombin induced platelet aggregation and the above mentioned mDia1 translocation.

CONCLUSIONS

PI3-kinase mediates the thrombin-induced platelet aggregation through mDia1 pathway.