ID:CFAB_HUMAN DESCRIPTION: RecName: Full=Complement factor B; EC=3.4.21.47; AltName: Full=C3/C5 convertase; AltName: Full=Glycine-rich beta glycoprotein; Short=GBG; AltName: Full=PBF2; AltName: Full=Properdin factor B; Contains: RecName: Full=Complement factor B Ba fragment; Contains: RecName: Full=Complement factor B Bb fragment; Flags: Precursor; FUNCTION: Factor B which is part of the alternate pathway of the complement system is cleaved by factor D into 2 fragments: Ba and Bb. Bb, a serine protease, then combines with complement factor 3b to generate the C3 or C5 convertase. It has also been implicated in proliferation and differentiation of preactivated B- lymphocytes, rapid spreading of peripheral blood monocytes, stimulation of lymphocyte blastogenesis and lysis of erythrocytes. Ba inhibits the proliferation of preactivated B-lymphocytes. CATALYTIC ACTIVITY: Cleavage of Arg-|-Ser bond in complement component C3 alpha-chain to yield C3a and C3b, and Arg-|-Xaa bond in complement component C5 alpha-chain to yield C5a and C5b. SUBUNIT: Monomer. SUBCELLULAR LOCATION: Secreted. POLYMORPHISM: Two major variants, F and S, and 2 minor variants, as well as at least 14 very rare variants, have been identified. The variants His-9 and Gln-32 are associated with a reduced risk of age-related macular degeneration (ARMD) [MIM:603075]. ARMD is a multifactorial eye disease and the most common cause of irreversible vision loss in the developed world. DISEASE: Defects in CFB are a cause of susceptibility to hemolytic uremic syndrome atypical type 4 (AHUS4) [MIM:612924]. An atypical form of hemolytic uremic syndrome. It is a complex genetic disease characterized by microangiopathic hemolytic anemia, thrombocytopenia, renal failure and absence of episodes of enterocolitis and diarrhea. In contrast to typical hemolytic uremic syndrome, atypical forms have a poorer prognosis, with higher death rates and frequent progression to end-stage renal disease. Note=Susceptibility to the development of atypical hemolytic uremic syndrome can be conferred by mutations in various components of or regulatory factors in the complement cascade system. Other genes may play a role in modifying the phenotype. SIMILARITY: Belongs to the peptidase S1 family. SIMILARITY: Contains 1 peptidase S1 domain. SIMILARITY: Contains 3 Sushi (CCP/SCR) domains. SIMILARITY: Contains 1 VWFA domain. WEB RESOURCE: Name=GeneReviews; URL="http://www.ncbi.nlm.nih.gov/sites/GeneTests/lab/gene/CFB"; WEB RESOURCE: Name=SeattleSNPs; URL="http://pga.gs.washington.edu/data/bf/";
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
Pfam Domains: PF00084 - Sushi repeat (SCR repeat) PF00089 - Trypsin PF00092 - von Willebrand factor type A domain PF13519 - von Willebrand factor type A domain
ModBase Predicted Comparative 3D Structure on P00751
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
US Server
Sequence and Links to Tools and Databases 
Common Gene Haplotype Alleles 
