Factor IX

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Coagulation factor IX (plasma thromboplastic component, Christmas disease, hemophilia B)
PDB rendering based on 1cfh.
Available structures: 1cfh, 1cfi, 1edm, 1ixa, 1j34, 1j35, 1mgx, 1nl0, 1rfn
Identifiers
Symbol(s) F9; FIX; GLA domain; HEMB; MGC129641; MGC129642; PTC
External IDs OMIM: 306900 MGI: 88384 HomoloGene: 106
RNA expression pattern

More reference expression data
Orthologs
Human Mouse
Entrez 2158 14071
Ensembl ENSG00000101981 ENSMUSG00000031138
Uniprot P00740 A0JLY3
Refseq NM_000133 (mRNA)
NP_000124 (protein)		 NM_007979 (mRNA)
NP_032005 (protein)
Location Chr X: 138.44 - 138.47 Mb Chr X: 56.35 - 56.38 Mb
Pubmed search [1] [2]

Factor IX (or Christmas factor) is one of the serine proteases (EC 3.4.21.22) of the coagulation system; it belongs to peptidase family S1. Deficiency of this protein causes hemophilia B. It was discovered after a young boy named Stephen Christmas was found to be lacking this exact factor, leading to hemophilia, in 1952.[1]

Contents

[edit] Physiology

Factor IX is inactive unless activated by factor XIa (of the contact pathway) or factor VIIa (of the tissue factor pathway). When activated into factor IXa, it acts by hydrolysing one arginine-isoleucine bond in factor X to form factor Xa. It requires calcium, membrane phospholipids, and factor VIII as cofactors to do so.

[edit] Genetics

The gene for factor IX is located on the X chromosome (Xq27.1-q27.2). It was first cloned in 1982 by Kotoku Kurachi and Earl Davie.[2]

Polly, a transgenic cloned Poll Dorset sheep carrying the gene for factor IX, was produced by Dr Ian Wilmut at the Roslin Institute in 1997.[3]

[edit] Role in disease

Deficiency of factor IX causes Christmas disease (hemophilia B). Over 100 mutations of factor IX have been described; some cause no symptoms, but many lead to a significant bleeding disorder.

[edit] References

  1. ^ Biggs RA, Douglas AS, MacFarlane RG, Dacie JV, Pittney WR, Merskey C, O'Brien JR. Christmas disease: a condition previously mistaken for haemophilia. Br Med J 1952;2:1378-1382. PMID 12997790.
  2. ^ Kurachi K, Davie E (1982). "Isolation and characterization of a cDNA coding for human factor IX". Proc Natl Acad Sci U S A 79 (21): 6461-4. doi:10.1073/pnas.79.21.6461. PMID 6959130. 
  3. ^ Nicholl D. (2002). An Introduction to Genetic Engineering Second Edition. Cambridge University Press, 257. 

[edit] Further reading

  • Davie EW, Fujikawa K (1975). "Basic mechanisms in blood coagulation.". Annu. Rev. Biochem. 44: 799-829. doi:10.1146/annurev.bi.44.070175.004055. PMID 237463. 
  • Sommer SS (1992). "Assessing the underlying pattern of human germline mutations: lessons from the factor IX gene.". FASEB J. 6 (10): 2767-74. PMID 1634040. 
  • Lenting PJ, van Mourik JA, Mertens K (1999). "The life cycle of coagulation factor VIII in view of its structure and function.". Blood 92 (11): 3983-96. PMID 9834200. 
  • Lowe GD (2002). "Factor IX and thrombosis.". Br. J. Haematol. 115 (3): 507-13. doi:10.1046/j.1365-2141.2001.03186.x. PMID 11736930. 
  • O'Connell NM (2004). "Factor XI deficiency--from molecular genetics to clinical management.". Blood Coagul. Fibrinolysis 14 Suppl 1: S59-64. PMID 14567539. 
  • Du X (2007). "Signaling and regulation of the platelet glycoprotein Ib-IX-V complex.". Curr. Opin. Hematol. 14 (3): 262-9. doi:10.1097/MOH.0b013e3280dce51a. PMID 17414217. 
v • d • e
Proteins: coagulation
Coagulation factors
primary hemostasis: vWF

intrinsic pathway: HMWK/Bradykinin - Kallikrein - Hageman / FXII - FXI - FIX - FVIII

extrinsic pathway: Tissue factor / FIII - FVII

common pathway: FX - FV - (Pro)thrombin / FII, Fibrin / FI - FXIII
Inhibitors
Fibrinolysis
v • d • e
Endopeptidases: serine proteases/serine endopeptidases (EC 3.4.21)
Digestive enzymes
Coagulation
Complement system
Other immune system
Venombin
Other
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