Platelet moesin interacts with PECAM-1 (CD31).

Platelet activation results in formation of filopodia and cell spreading by extension of lamellae. Moesin is a member of the ezrin/radixin/moesin (ERM) family of proteins, which localize in cell extensions like filopodia and function as cross-linkers between the actin cytoskeleton and the plasma membrane. Here we investigated whether the adhesion molecule PECAM-1 (CD31) is a membrane-binding partner for moesin in platelets. Our data show that moesin co-immunoprecipitated with PECAM-1 in lysates from thrombin-stimulated, but not resting platelets. Furthermore, PECAM-1 co-localized with moesin at the cell periphery and in filopodia of glass-activated platelets. Our observations suggest that moesin may play a role in platelet adhesion, linking PECAM-1 with the actin cytoskeleton.