Fucoidan is a novel platelet agonist for the C-type lectin-like receptor 2 (CLEC-2)

J Biol Chem. 2013 Mar 15;288(11):7717-7726. doi: 10.1074/jbc.M112.424473. Epub 2013 Jan 22.


Fucoidan, a sulfated polysaccharide from Fucus vesiculosus, decreases bleeding time and clotting time in hemophilia, possibly through inhibition of tissue factor pathway inhibitor. However, its effect on platelets and the receptor by which fucoidan induces cellular processes has not been elucidated. In this study, we demonstrate that fucoidan induces platelet activation in a concentration-dependent manner. Fucoidan-induced platelet activation was completely abolished by the pan-Src family kinase (SFK) inhibitor, PP2, or when Syk is inhibited. PP2 abolished phosphorylations of Syk and Phospholipase C-γ2. Fucoidan-induced platelet activation had a lag phase, which is reminiscent of platelet activation by collagen and CLEC-2 receptor agonists. Platelet activation by fucoidan was only slightly inhibited in FcRγ-chain null mice, indicating that fucoidan was not acting primarily through GPVI receptor. On the other hand, fucoidan-induced platelet activation was inhibited in platelet-specific CLEC-2 knock-out murine platelets revealing CLEC-2 as a physiological target of fucoidan. Thus, our data show fucoidan as a novel CLEC-2 receptor agonist that activates platelets through a SFK-dependent signaling pathway. Furthermore, the efficacy of fucoidan in hemophilia raises the possibility that decreased bleeding times could be achieved through activation of platelets.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Anticoagulants / pharmacology
  • Blood Platelets / drug effects*
  • Flow Cytometry / methods
  • Hemophilia A / drug therapy
  • Humans
  • Immunoprecipitation / methods
  • Lectins, C-Type / metabolism*
  • Membrane Glycoproteins / metabolism*
  • Mice
  • Mice, Knockout
  • Phosphorylation
  • Platelet Activation / drug effects
  • Polysaccharides / chemistry*
  • Receptor Protein-Tyrosine Kinases / metabolism
  • Signal Transduction
  • src-Family Kinases / metabolism


  • Anticoagulants
  • CLEC-2 protein, mouse
  • CLEC2B protein, human
  • Lectins, C-Type
  • Membrane Glycoproteins
  • Polysaccharides
  • fucoidan
  • Receptor Protein-Tyrosine Kinases
  • src-Family Kinases