Fungal phytotoxin fusicoccin for the treatmant and diagnosis of coagulation-correlated pathologies.

Fusicoccin is a fungal phytotoxin known to induce a strong and permanent activation of the plant plasma membrane H+-ATPase. Fusicoccin promotes the association of 14-3-3 proteins to a mode III binding motif located at the C-terminal end of the enzyme. Here we show that fusicoccin can stimulate binding of 14-3-3 proteins to the platelet protein Glycoprotein Ib, which also contains a mode III 14-3-3 binding sequence. Glycoprotein Ib is the platelet receptor for von Willebrand Factor and it is essential in the first step of the coagulation process. Fusicoccin binding promotes activation of Glycoprotein Ib and consequent adhesion of platelets to von Willebrand Factor, therefore triggering the aggregation process. Our data propose fusicoccin as a novel compound able to induce platelet aggregation. Therapeutic implications of this finding are also discussed.