Trombocit faktor 4 (PF4), ili hemokin (C-X-C motiv) ligand 4 (CXCL4), je mali citokin iz CXC hemokin familije. Ovaj hemokin se oslobađa iz alfa-granula aktiviranih trombocita u toku trombocit agregacije. On promoviše koagulaciju krvi putem dejstva na heparin-slične molekula. Iz tog razloga, za njega je predviđeno da igra ulogu in zarastanju rana i inflamacija.[1] Njegova glavna fiziološka uloga je neutralizacija heparin-sličnih molekula na endotelnoj površini krvnih sudova, čime se inhibira lokalna antitrombin III aktivnost i promoviše koagulacija.[2] On se obično nalazi u kompleksu sa proteoglikanom.[3]
Heparin:PF4 kompleks je antigen u heparin-indukovanoj trombocitopeniji, idiosinkratičnoj autoimunoj reakciji na administraciju antikoagulanta heparina.[6] PF4 autoantitela su bila nađena kod pacijenata sa trombozom i osobinama poput HIT ali ne pre administracije heparina.[7]
↑Eisman R, Surrey S, Ramachandran B, Schwartz E, Poncz M (1990). "Structural and functional comparison of the genes for human platelet factor 4 and PF4alt". Blood76 (2): 336–44. PMID1695112.
↑O'Donovan N, Galvin M, Morgan J (1999). "Physical mapping of the CXC chemokine locus on human chromosome 4". Cytogenet Cell Genet84 (1-2): 39–42. PMID10343098. doi:10.1159/000015209.
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Maurer AM, Zhou B, Han ZC (2007). "Roles of platelet factor 4 in hematopoiesis and angiogenesis.". Growth Factors24 (4): 242–52. PMID17381065. doi:10.1080/08977190600988225.
Walz DA, Wu VY, de Lamo R et al. (1978). "Primary structure of human platelet factor 4.". Thromb. Res.11 (6): 893–8. PMID601757. doi:10.1016/0049-3848(77)90117-7.CS1 održavanje: Eksplicitna upotreba et al. (link)
Nath N, Lowery CT, Niewiarowski S (1975). "Antigenic and antiheparin properties of human platelet factor 4 (PF4).". Blood45 (4): 537–50. PMID803847.
Hermodson M, Schmer G, Kurachi K (1977). "Isolation, crystallization, and primary amino acid sequence of human platelet factor 4.". J. Biol. Chem.252 (18): 6276–9. PMID893407.
Maione TE, Gray GS, Petro J et al. (1990). "Inhibition of angiogenesis by recombinant human platelet factor-4 and related peptides.". Science247 (4938): 77–9. PMID1688470. doi:10.1126/science.1688470.CS1 održavanje: Eksplicitna upotreba et al. (link)
Eisman R, Surrey S, Ramachandran B et al. (1990). "Structural and functional comparison of the genes for human platelet factor 4 and PF4alt.". Blood76 (2): 336–44. PMID1695112.CS1 održavanje: Eksplicitna upotreba et al. (link)
Han ZC, Bellucci S, Tenza D, Caen JP (1990). "Negative regulation of human megakaryocytopoiesis by human platelet factor 4 and beta thromboglobulin: comparative analysis in bone marrow cultures from normal individuals and patients with essential thrombocythaemia and immune thrombocytopenic purpura.". Br. J. Haematol.74 (4): 395–401. PMID2140694. doi:10.1111/j.1365-2141.1990.tb06325.x.
Poncz M, Surrey S, LaRocco P et al. (1987). "Cloning and characterization of platelet factor 4 cDNA derived from a human erythroleukemic cell line.". Blood69 (1): 219–23. PMID3098319.CS1 održavanje: Eksplicitna upotreba et al. (link)
Griffin CA, Emanuel BS, LaRocco P et al. (1987). "Human platelet factor 4 gene is mapped to 4q12----q21.". Cytogenet. Cell Genet.45 (2): 67–9. PMID3622011. doi:10.1159/000132431.CS1 održavanje: Eksplicitna upotreba et al. (link)
Brown KJ, Parish CR (1994). "Histidine-rich glycoprotein and platelet factor 4 mask heparan sulfate proteoglycans recognized by acidic and basic fibroblast growth factor.". Biochemistry33 (46): 13918–27. PMID7524669. doi:10.1021/bi00250a047.
Mayo KH, Roongta V, Ilyina E et al. (1995). "NMR solution structure of the 32-kDa platelet factor 4 ELR-motif N-terminal chimera: a symmetric tetramer.". Biochemistry34 (36): 11399–409. PMID7547867. doi:10.1021/bi00036a012.CS1 održavanje: Eksplicitna upotreba et al. (link)
Barker S, Mayo KH (1995). "Quarternary structure amplification of protein folding differences observed in 'native' platelet factor-4.". FEBS Lett.357 (3): 301–4. PMID7835432. doi:10.1016/0014-5793(94)01384-D.
Zhang X, Chen L, Bancroft DP et al. (1994). "Crystal structure of recombinant human platelet factor 4.". Biochemistry33 (27): 8361–6. PMID8031770. doi:10.1021/bi00193a025.CS1 održavanje: Eksplicitna upotreba et al. (link)
Horne MK (1993). "The effect of secreted heparin-binding proteins on heparin binding to platelets.". Thromb. Res.70 (1): 91–8. PMID8511754. doi:10.1016/0049-3848(93)90226-E.
Kolset SO, Mann DM, Uhlin-Hansen L et al. (1996). "Serglycin-binding proteins in activated macrophages and platelets.". J. Leukoc. Biol.59 (4): 545–54. PMID8613703.CS1 održavanje: Eksplicitna upotreba et al. (link)
1f9r: Kristalna struktura trombocit faktora 4 mutant 1
1f9s: Kristalna struktura trombocit faktora 4 mutant 2
1pfm: PF4-M2 himerični mutant sa prvih 10 N-terminalnih R-PF4 ostataka zamenjenih sa N-terminalnim ostacima IL8 sekvence. Modeli 1-15 iz seta sa 27-modela.
1pfn: PF4-M2 himerični mutant sa prvih 10 N-terminalnih R-PF4 ostataka zamenjenih sa N-terminalnim ostacima IL8 sekvence. Modeli 16-27 iz seta sa 27-modela.
1rhp: Kristalna struktura rekombinantnog ljudskog trombocit faktora 4