Factor D

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complement factor D (adipsin)
Factor D.jpg
Factor D in Homo sapiens[1][2]
Identifiers
Symbol CFD
Alt. symbols DF, PFD
Entrez 1675
HUGO 2771
OMIM 134350
RefSeq NM_001928
UniProt P00746
Other data
Locus Chr. 19 p13.3

Factor D (EC 3.4.21.46, C3 proactivator convertase, properdin factor D esterase, factor D (complement), complement factor D, CFD, adipsin) a protein which in humans is encoded by the CFD gene.[3] Factor D is involved in the alternative complement pathway of the complement system where it cleaves factor B.

Function[edit]

The protein encoded by this gene is a member of the trypsin family of peptidases. The encoded protein is a component of the alternative complement pathway best known for its role in humoral suppression of infectious agents. This protein is also a serine protease that is secreted by adipocytes into the bloodstream. Finally, the encoded protein has a high level of expression in fat, suggesting a role for adipose tissue in immune system biology.[3]

Alternative pathway. ( 4. Is factor D cleaving B to Bb and Ba)

Factor D is a serine protease that stimulates glucose transport for triglyceride accumulation in fats cells and inhibits lipolysis.[4]

Clinical significance[edit]

The level of Factor D is decreased[5] in the obese, this reduction may be due to high activity or resistance but exact cause is not totally known.

Structure[edit]

All members of the chymotrypsin family of serine proteases have very similar structures. In all cases, including factor D, there are two antiparallel β-barrel domains with each barrel containing six β-strands with the same typology in all enzymes. The major difference in backbone structure between Factor D and the other serine proteases of the chymotrpsin family is in the surface loops connecting the secondary structural elements. Factor D displays different conformations of major catalytic and substrate-binding residues typically found in the chrotrypsin family. These features suggest the catalytic activity of factor D is prohibited unless conformational changes are induced by a realignment.[6]

References[edit]

  1. ^ PDB: 1HFD
  2. ^ Narayana SV, Carson M, el-Kabbani O, Kilpatrick JM, Moore D, Chen X, Bugg CE, Volanakis JE, DeLucas LJ (1994). "Structure of human factor D. A complement system protein at 2.0 A resolution". Journal of Molecular Biology. 235 (2): 695–708. PMID 8289289. doi:10.1006/jmbi.1994.1021. 
  3. ^ a b EntrezGene 1675
  4. ^ Ronti T, Lupattelli G, Mannarino E (2006). "The endocrine function of adipose tissue: an update". Clinical Endocrinology. 64 (4): 355–65. PMID 16584505. doi:10.1111/j.1365-2265.2006.02474.x. 
  5. ^ Flier JS, Cook KS, Usher P, Spiegelman BM (1987). "Severely impaired adipsin expression in genetic and acquired obesity". Science. 237 (4813): 405–8. PMID 3299706. doi:10.1126/science.3299706. 
  6. ^ Volanakis JE, Narayana SV (1996). "Complement factor D, a novel serine protease". Protein Science. 5 (4): 553–64. PMC 2143395Freely accessible. PMID 8845746. doi:10.1002/pro.5560050401. 

External links[edit]

This article incorporates text from the United States National Library of Medicine, which is in the public domain.