CFB, Official Symbol CFBprovided by HGNC Official Full Name complement factor Bprovided by HGNC Primary source HGNC:HGNC:1037 See related Ensembl:ENSG00000243649 MIM:138470; AllianceGenome:HGNC:1037 Gene type protein coding RefSeq status REVIEWED Organism Homo sapiens Lineage Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo Also known as BF; FB; BFD; GBG; CFAB; CFBD; PBF2; AHUS4; FBI12; H2-Bf; ARMD14 Summary This gene encodes complement factor B, a component of the alternative pathway of complement activation. Factor B circulates in the blood as a single chain polypeptide. Upon activation of the alternative pathway, it is cleaved by complement factor D yielding the noncatalytic chain Ba and the catalytic subunit Bb. The active subunit Bb is a serine protease which associates with C3b to form the alternative pathway C3 convertase. Bb is involved in the proliferation of preactivated B lymphocytes, while Ba inhibits their proliferation. This gene localizes to the major histocompatibility complex (MHC) class III region on chromosome 6. This cluster includes several genes involved in regulation of the immune reaction. Polymorphisms in this gene are associated with a reduced risk of age-related macular degeneration. The polyadenylation site of this gene is 421 bp from the 5' end of the gene for complement component 2. [provided by RefSeq, Jul 2008] Expression Biased expression in liver (RPKM 870.3), gall bladder (RPKM 108.2) and 2 other tissues See more Orthologs mouse all