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platelet factor 4; PF-4; C-X-C motif chemokine 4; iroplact; oncostatin-A (PF4, CXCL4, SCYB4)
Function:
- component of platelet alpha granules
- released during platelet aggregation
- binds both heparan-sulfate & chondroitan-sulfate
- neutralizes the anticoagulant effect of heparin because it binds more strongly to heparin than to the chondroitin-4-sulfate chains of the carrier
- chemotactic for neutrophils & monocytes
- inhibits endothelial cell proliferation
- the short form is a more potent inhibitor than the longer form
- binds non-covalently to a proteoglycan molecule
Structure:
- homotetramer
- belongs to the intercrine alpha (chemokine CxC) family
Compartment: secreted
Specific
platelet factor 4 variant; C-X-C motif chemokine 4 variant; CXCL4L1; PF4alt; PF4var1 (PF4V1, CXCL4V1, SCYB4V1)
General
CXC chemokine; alpha chemokine
Properties
SIZE: entity length = 101 aa
MW = 11 kD
COMPARTMENT: extracellular compartment
MOTIF: signal sequence {1-31}
cysteine residue {C41}
MODIFICATION: cysteine residue {C67}
cysteine residue {C43}
MODIFICATION: cysteine residue {C83}
cysteine residue {C67}
MODIFICATION: cysteine residue {C41}
cysteine residue {C83}
MODIFICATION: cysteine residue {C43}
SECRETED-BY: platelet
References
- UniProt :accession P02776
- Wikipedia; Note: CXCL4 entry
http://en.wikipedia.org/wiki/CXCL4
- Ruoslahti E, Yamaguchi Y.
Proteoglycans as modulators of growth factor activities.
Cell. 1991 Mar 8;64(5):867-9. Review.
PMID: 2001586
Databases & Figures
OMIM 173460
UniProt P02776
Pfam PF00048
Entrez Gene 5196
Kegg hsa:5196
CXC ligand and receptor binding