CXCL4

CXCL4 is a small cytokine belonging to the CXC chemokine family that is also known as platelet factor 4 (PF4). It is released from the alpha-granules of activated platelets and binds with high affinity to heparin. Its major physiologic role appears to be neutralization of heparin-like molecules on the endothelial surface of blood vessels, thereby inhibiting local antithrombin III activity and promoting coagulation. As a strong chemoattractant for neutrophils and fibroblasts, CXCL4 likely has a role in inflammation and wound repair.

Structure

CXCL4 is a 70-amino acid protein with a molecular weight of 7800 daltons. The structure of CXCL4 consists of a core of three antiparallel beta sheets, followed by a C-terminal alpha helix. The protein has a heparin binding site and a receptor binding site, which are located on opposite sides of the molecule.

Function

CXCL4 is secreted by activated platelets and encourages clot formation by attracting neutrophils and fibroblasts and by inhibiting the anticoagulant effects of heparin. CXCL4 also has non-hemostatic roles, including regulating monocyte survival and dendritic cell function. CXCL4 can be chemotactic for various cell types, including neutrophils, fibroblasts, and monocytes, and it can inhibit the proliferation of certain types of tumor cells. CXCL4 also plays a role in wound healing and inflammation.

Clinical significance

Elevated levels of CXCL4 have been found in patients with various conditions such as rheumatoid arthritis, atherosclerosis, and certain cancers. It is also involved in the pathogenesis of scleroderma. Furthermore, CXCL4 is a potential biomarker for platelet activation in diseases such as cardiovascular disease, sepsis, and cancer.

See also

• Chemokine
• Cytokine
• Platelet

CXCL4 Resources
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