Factor D
| complement factor D (adipsin) | |
|---|---|
|
|
| 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]
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]
- ^ PDB: 1HFD
- ^ 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.
- ^ a b EntrezGene 1675
- ^ 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.
- ^ 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.
- ^ Volanakis JE, Narayana SV (1996). "Complement factor D, a novel serine protease". Protein Science. 5 (4): 553–64. PMC 2143395
. PMID 8845746. doi:10.1002/pro.5560050401.
External links[edit]
- Complement Factor D at the US National Library of Medicine Medical Subject Headings (MeSH)
This article incorporates text from the United States National Library of Medicine, which is in the public domain.
