CXCL4 Human Active Protein

This gene encodes a member of the CXC chemokine family. This chemokine is released from the alpha granules of activated platelets in the form of a homotetramer which has high affinity for heparin and is involved in platelet aggregation. This protein is chemotactic for numerous other cell type and also functions as an inhibitor of hematopoiesis, angiogenesis and T-cell function. [provided by RefSeq, Mar 2012]

PF4: Released during platelet aggregation. Neutralizes the anticoagulant effect of heparin because it binds more strongly to heparin than to the chondroitin-4-sulfate chains of the carrier molecule. Chemotactic for neutrophils and monocytes. Inhibits endothelial cell proliferation, the short form is a more potent inhibitor than the longer form. Belongs to the intercrine alpha (chemokine CxC) family.

Protein type: Motility/polarity/chemotaxis; Secreted; Apoptosis; Chemokine; Secreted, signal peptide

Chromosomal Location of Human Ortholog: 4q12-q21

Cellular Component: extracellular space; extracellular region

Molecular Function: heparin binding; CXCR3 chemokine receptor binding; chemokine activity

Biological Process: negative regulation of cytolysis; platelet activation; cytokine and chemokine mediated signaling pathway; leukocyte chemotaxis; response to lipopolysaccharide; positive regulation of leukocyte chemotaxis; positive regulation of cAMP metabolic process; positive regulation of tumor necrosis factor production; negative regulation of megakaryocyte differentiation; regulation of cell proliferation; G-protein coupled receptor protein signaling pathway; negative regulation of angiogenesis; platelet degranulation; negative regulation of MHC class II biosynthetic process; positive regulation of transcription from RNA polymerase II promoter; immune response; inflammatory response; positive regulation of macrophage differentiation; blood coagulation