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]
Kratke činjenice Dostupne strukture, Identifikatori ...
Zatvori
PF4 je izaziva hemotaksu neutrofila, fibroblasta i monocita, i interaguje sa varijantom hemokin receptora CXCR3, poznatom kao CXCR3B.[4] Gen za ljudski PF4 je lociran na ljudskom hromozomu 4.[5]
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]
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Lasagni L, Francalanci M, Annunziato F, Lazzeri E, Giannini S, Cosmi L, Sagrinati C, Mazzinghi B, Orlando C, Maggi E, Marra F, Romagnani S, Serio M, Romagnani P (2003). „An alternatively spliced variant of CXCR3 mediates the inhibition of endothelial cell growth induced by IP-10, Mig, and I-TAC, and acts as functional receptor for platelet factor 4”. J Exp Med 197 (11): 1537–49. DOI:10.1084/jem.20021897. PMC 2193908. PMID 12782716.
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- Maurer AM, Zhou B, Han ZC (2007). „Roles of platelet factor 4 in hematopoiesis and angiogenesis.”. Growth Factors 24 (4): 242–52. DOI:10.1080/08977190600988225. PMID 17381065.
- Deuel TF, Keim PS, Farmer M, Heinrikson RL (1977). „Amino acid sequence of human platelet factor 4.”. Proc. Natl. Acad. Sci. U.S.A. 74 (6): 2256–8. DOI:10.1073/pnas.74.6.2256. PMC 432148. PMID 267922.
- Walz DA, Wu VY, de Lamo R, et al. (1978). „Primary structure of human platelet factor 4.”. Thromb. Res. 11 (6): 893–8. DOI:10.1016/0049-3848(77)90117-7. PMID 601757.
- Nath N, Lowery CT, Niewiarowski S (1975). „Antigenic and antiheparin properties of human platelet factor 4 (PF4).”. Blood 45 (4): 537–50. PMID 803847.
- 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. PMID 893407.
- Maione TE, Gray GS, Petro J, et al. (1990). „Inhibition of angiogenesis by recombinant human platelet factor-4 and related peptides.”. Science 247 (4938): 77–9. DOI:10.1126/science.1688470. PMID 1688470.
- Eisman R, Surrey S, Ramachandran B, et al. (1990). „Structural and functional comparison of the genes for human platelet factor 4 and PF4alt.”. Blood 76 (2): 336–44. PMID 1695112.
- 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. DOI:10.1111/j.1365-2141.1990.tb06325.x. PMID 2140694.
- Poncz M, Surrey S, LaRocco P, et al. (1987). „Cloning and characterization of platelet factor 4 cDNA derived from a human erythroleukemic cell line.”. Blood 69 (1): 219–23. PMID 3098319.
- 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. DOI:10.1159/000132431. PMID 3622011.
- Senior RM, Griffin GL, Huang JS, et al. (1983). „Chemotactic activity of platelet alpha granule proteins for fibroblasts.”. J. Cell Biol. 96 (2): 382–5. DOI:10.1083/jcb.96.2.382. PMC 2112304. PMID 6187750.
- Morgan FJ, Begg GS, Chesterman CN (1980). „Complete covalent structure of human platelet factor 4.”. Thromb. Haemost. 42 (5): 1652–60. PMID 6445090.
- Deuel TF, Senior RM, Chang D, et al. (1981). „Platelet factor 4 is chemotactic for neutrophils and monocytes.”. Proc. Natl. Acad. Sci. U.S.A. 78 (7): 4584–7. DOI:10.1073/pnas.78.7.4584. PMC 319837. PMID 6945600.
- Brown KJ, Parish CR (1994). „Histidine-rich glycoprotein and platelet factor 4 mask heparan sulfate proteoglycans recognized by acidic and basic fibroblast growth factor.”. Biochemistry 33 (46): 13918–27. DOI:10.1021/bi00250a047. PMID 7524669.
- 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.”. Biochemistry 34 (36): 11399–409. DOI:10.1021/bi00036a012. PMID 7547867.
- Barker S, Mayo KH (1995). „Quarternary structure amplification of protein folding differences observed in 'native' platelet factor-4.”. FEBS Lett. 357 (3): 301–4. DOI:10.1016/0014-5793(94)01384-D. PMID 7835432.
- Zhang X, Chen L, Bancroft DP, et al. (1994). „Crystal structure of recombinant human platelet factor 4.”. Biochemistry 33 (27): 8361–6. DOI:10.1021/bi00193a025. PMID 8031770.
- Horne MK (1993). „The effect of secreted heparin-binding proteins on heparin binding to platelets.”. Thromb. Res. 70 (1): 91–8. DOI:10.1016/0049-3848(93)90226-E. PMID 8511754.
- 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. PMID 8613703.