P00751 · CFAB_HUMAN

  • Protein
    Complement factor B
  • Gene
    CFB
  • Status
    UniProtKB reviewed (Swiss-Prot)
  • Amino acids
  • Protein existence
    Evidence at protein level
  • Annotation score
    5/5

Function

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.
    EC:3.4.21.47 (UniProtKB | ENZYME | Rhea)

Features

Showing features for active site.

1764100200300400500600700
TypeIDPosition(s)Description
Active site526Charge relay system
Active site576Charge relay system
Active site699Charge relay system

GO annotations

all annotationsall molecular functionvirus receptor activitydna bindingrna bindingcytoskeletal motor activitycatalytic activitygtpase activitystructural molecule activitytransporter activitycytoskeletal protein bindinglipid bindingcyclase activityantioxidant activityoxidoreductase activitytransferase activityhydrolase activitylyase activityisomerase activityligase activityprotein tag activitycargo receptor activityhistone bindingprotein folding chaperonetranslation regulator activitynutrient reservoir activityreceptor ligand activitymolecular transducer activitymolecular adaptor activitytoxin activitycell adhesion mediator activitymolecular function regulator activityvirus coreceptor activitycatalytic activity, acting on a proteincatalytic activity, acting on dnacatalytic activity, acting on rnamolecular carrier activitytranscription regulator activitygeneral transcription initiation factor activitymolecular sensor activitymolecular sequestering activityatp-dependent activityother molecular functionall biological processmitotic cell cyclecytokinesiscytoplasmic translationimmune system processmuscle system processcirculatory system processrenal system processrespiratory system processcarbohydrate metabolic processgeneration of precursor metabolites and energydna replicationdna repairdna recombinationchromatin organizationdna-templated transcriptionregulation of dna-templated transcriptiontrna metabolic processprotein foldingprotein glycosylationamino acid metabolic processmodified amino acid metabolic processlipid metabolic processvitamin metabolic processsulfur compound metabolic processintracellular protein transportnucleocytoplasmic transportautophagyinflammatory responsemitochondrion organizationcytoskeleton organizationmicrotubule-based movementperoxisome organizationlysosome organizationchromosome segregationcell adhesionestablishment or maintenance of cell polarityprogrammed cell deathphotosynthesismrna metabolic processsnrna metabolic processvesicle-mediated transportreproductive processdigestive system processsignalingcell differentiationprotein catabolic processextracellular matrix organizationregulatory ncrna-mediated gene silencingtelomere organizationcell junction organizationwound healingribosome biogenesiscilium organizationanatomical structure developmentcell motilitynervous system processendocrine processprotein maturationtransmembrane transportnucleobase-containing small molecule metabolic processhepaticobiliary system processmembrane organizationprotein-containing complex assemblycell wall organization or biogenesisnitrogen cycle metabolic processprotein localization to plasma membranedefense response to other organismdetoxificationmeiotic nuclear divisionmitotic nuclear divisionmitochondrial gene expressioncarbohydrate derivative metabolic processother biological processall cellular componentnuclear chromosomeextracellular regionextracellular spacecell wallnucleusnuclear envelopenucleoplasmchromosomenucleolusmitochondrionlysosomeendosomevacuoleperoxisomeendoplasmic reticulumgolgi apparatuslipid dropletmicrotubule organizing centercytosolribosomecytoskeletonplasma membraneciliumplastidthylakoidexternal encapsulating structureextracellular matrixcytoplasmic vesicleorganelleother cellular component
Cell color indicative of number of GO terms
AspectTerm
Cellular Componentblood microparticle
Cellular Componentextracellular exosome
Cellular Componentextracellular region
Cellular Componentextracellular space
Cellular Componentplasma membrane
Molecular Functioncomplement binding
Molecular Functionserine-type endopeptidase activity
Biological Processcomplement activation
Biological Processcomplement activation, alternative pathway
Biological Processproteolysis
Biological Processresponse to bacterium

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

Gene names

    • Name
      CFB
    • Synonyms
      BF, BFD

Organism names

  • Taxonomic identifier
  • Taxonomic lineage
    Eukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Euarchontoglires > Primates > Haplorrhini > Catarrhini > Hominidae > Homo

Accessions

  • Primary accession
    P00751
  • Secondary accessions
    • B0QZQ6
    • O15006
    • Q29944
    • Q53F89
    • Q5JP67

Proteomes

Organism-specific databases

Disease & Variants

Involvement in disease

Macular degeneration, age-related, 14 (ARMD14)

  • Note
    • Disease susceptibility may be associated with variants affecting the gene represented in this entry. Haplotype analyses have identified a statistically significant common risk haplotype and two protective haplotypes. CFB variant His-9 and C2 variant Asp-318, as well as CFB variant Gln-32 and a variant in intron 10 of C2, confer a significantly reduced risk of AMD
  • Description
    A form of age-related macular degeneration, a multifactorial eye disease and the most common cause of irreversible vision loss in the developed world. In most patients, the disease is manifest as ophthalmoscopically visible yellowish accumulations of protein and lipid that lie beneath the retinal pigment epithelium and within an elastin-containing structure known as Bruch membrane.
  • See also
    MIM:615489

Hemolytic uremic syndrome, atypical, 4 (AHUS4)

  • Note
    • Disease susceptibility is associated with variants affecting the gene represented in this entry. 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
  • Description
    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.
  • See also
    MIM:612924
Natural variants in AHUS4
Variant IDPosition(s)ChangeDescription
VAR_063659166S>Pin AHUS4
VAR_063660203R>Qin AHUS4; dbSNP:rs745794224
VAR_063661242I>Lin AHUS4; dbSNP:rs144812066
VAR_063221286F>Lin AHUS4; gain-of-function mutation that results in enhanced formation of the C3bBb; dbSNP:rs117905900
VAR_063222323K>Ein AHUS4; gain-of-function mutation that results in enhanced formation of the C3bBb; dbSNP:rs121909748
VAR_063662323K>Qin AHUS4
VAR_063663458M>Iin AHUS4; dbSNP:rs200837114
VAR_063664533K>Rin AHUS4; benign; dbSNP:rs149101394

Complement factor B deficiency (CFBD)

  • Note
    • The disease is caused by variants affecting the gene represented in this entry
  • Description
    An immunologic disorder characterized by increased susceptibility to bacterial infections, particularly Neisseria infections, due to a defect in the alternative complement pathway.
  • See also
    MIM:615561

Features

Showing features for natural variant, mutagenesis.

TypeIDPosition(s)Description
Natural variantVAR_0162749may be associated with a reduced risk for age-related macular degeneration; dbSNP:rs4151667
Natural variantVAR_00649328in allele FA; requires 2 nucleotide substitutions
Natural variantVAR_00649228in allele S
Natural variantVAR_00649432in allele S; may be associated with a reduced risk for age-related macular degeneration; dbSNP:rs641153
Natural variantVAR_01627532in dbSNP:rs12614
Natural variantVAR_063659166in AHUS4
Natural variantVAR_063660203in AHUS4; dbSNP:rs745794224
Natural variantVAR_063661242in AHUS4; dbSNP:rs144812066
Natural variantVAR_016276252in dbSNP:rs4151651
Natural variantVAR_063221286in AHUS4; gain-of-function mutation that results in enhanced formation of the C3bBb; dbSNP:rs117905900
Natural variantVAR_063222323in AHUS4; gain-of-function mutation that results in enhanced formation of the C3bBb; dbSNP:rs121909748
Natural variantVAR_063662323in AHUS4
Mutagenesis348-350Decreases binding to the pro-C3-convertase complex. Does not affect Complement C3 beta chain binding.
Natural variantVAR_063663458in AHUS4; dbSNP:rs200837114
Natural variantVAR_063664533in AHUS4; benign; dbSNP:rs149101394
Natural variantVAR_016277565in dbSNP:rs4151659
Natural variantVAR_016278651in dbSNP:rs4151660
Natural variantVAR_006495736in allele FA

Variants

We now provide the "Disease & Variants" viewer in its own tab.

The viewer provides 1,283 variants from UniProt as well as other sources including ClinVar and dbSNP.

Go to variant viewer

Keywords

Organism-specific databases

Miscellaneous

Chemistry

Genetic variation databases

PTM/Processing

Features

Showing features for signal, chain, disulfide bond, glycosylation.

TypeIDPosition(s)Description
Signal1-25
ChainPRO_000002754626-259Complement factor B Ba fragment
ChainPRO_000002754526-764Complement factor B
Disulfide bond37↔76
Disulfide bond62↔98
Disulfide bond103↔145
Glycosylation122N-linked (GlcNAc...) asparagine
Disulfide bond131↔158
Glycosylation142N-linked (GlcNAc...) asparagine
Disulfide bond165↔205
Disulfide bond191↔218
ChainPRO_0000027547260-764Complement factor B Bb fragment
Glycosylation285N-linked (GlcNAc...) asparagine
Glycosylation291N-linked (Glc) (glycation) lysine
Glycosylation378N-linked (GlcNAc...) asparagine
Disulfide bond478↔596
Disulfide bond511↔527
Disulfide bond599↔615
Disulfide bond656↔682
Disulfide bond695↔725

Keywords

Proteomic databases

2D gel databases

PTM databases

Expression

Gene expression databases

Organism-specific databases

Interaction

Subunit

Monomer (PubMed:19574954).
Part of the C3-convertase enzyme complex comprised of Complement C3 beta chain (C3b) and Complement factor B Bb fragment (Bb) and CFP (PubMed:28264884, PubMed:31507604).
Interacts to C3b; this interaction is dependent on the presence of Mg2+ (PubMed:28264884, PubMed:31507604).
Interacts to CFP; this interaction contributes to the stabilization of the active C3-convertase enzyme complex (PubMed:31507604).

Binary interactions

TypeEntry 1Entry 2Number of experimentsIntact
BINARY P00751C3 P010243EBI-1223668, EBI-905851
BINARY P00751CFHR4 Q92496-12EBI-1223668, EBI-22033617
BINARY P00751CFHR4 Q92496-32EBI-1223668, EBI-22033638
View interactors in UniProtKB
View CPX-5381 in Complex Portal

Protein-protein interaction databases

Chemistry

Miscellaneous

Family & Domains

Features

Showing features for domain.

TypeIDPosition(s)Description
Domain35-100Sushi 1
Domain101-160Sushi 2
Domain163-220Sushi 3
Domain270-469VWFA
Domain477-757Peptidase S1

Domain

The unliganded VWA domain has an inactive 'locked' conformation whereby the scissile Arg-259|Lys-260 bond is protected from proteolytic activation.

Sequence similarities

Belongs to the peptidase S1 family.

Keywords

Phylogenomic databases

Family and domain databases

Sequence & Isoform

Align isoforms (2)
  • Sequence status
    Complete
  • Sequence processing
    The displayed sequence is further processed into a mature form.

This entry describes 2 isoforms produced by Alternative splicing.

P00751-1

This isoform has been chosen as the canonical sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

  • Length
    764
  • Mass (Da)
    85,533
  • Last updated
    1994-10-01 v2
  • Checksum
    8BB6C101CC6AC200
MGSNLSPQLCLMPFILGLLSGGVTTTPWSLARPQGSCSLEGVEIKGGSFRLLQEGQALEYVCPSGFYPYPVQTRTCRSTGSWSTLKTQDQKTVRKAECRAIHCPRPHDFENGEYWPRSPYYNVSDEISFHCYDGYTLRGSANRTCQVNGRWSGQTAICDNGAGYCSNPGIPIGTRKVGSQYRLEDSVTYHCSRGLTLRGSQRRTCQEGGSWSGTEPSCQDSFMYDTPQEVAEAFLSSLTETIEGVDAEDGHGPGEQQKRKIVLDPSGSMNIYLVLDGSDSIGASNFTGAKKCLVNLIEKVASYGVKPRYGLVTYATYPKIWVKVSEADSSNADWVTKQLNEINYEDHKLKSGTNTKKALQAVYSMMSWPDDVPPEGWNRTRHVIILMTDGLHNMGGDPITVIDEIRDLLYIGKDRKNPREDYLDVYVFGVGPLVNQVNINALASKKDNEQHVFKVKDMENLEDVFYQMIDESQSLSLCGMVWEHRKGTDYHKQPWQAKISVIRPSKGHESCMGAVVSEYFVLTAAHCFTVDDKEHSIKVSVGGEKRDLEIEVVLFHPNYNINGKKEAGIPEFYDYDVALIKLKNKLKYGQTIRPICLPCTEGTTRALRLPPTTTCQQQKEELLPAQDIKALFVSEEEKKLTRKEVYIKNGDKKGSCERDAQYAPGYDKVKDISEVVTPRFLCTGGVSPYADPNTCRGDSGGPLIVHKRSRFIQVGVISWGVVDVCKNQKRQKQVPAHARDFHINLFQVLPWLKEKLQDEDLGFL

P00751-2

  • Name
    2
  • See also
    sequence in UniParc or sequence clusters in UniRef
  • Differences from canonical
    • 543-621: GEKRDLEIEVVLFHPNYNINGKKEAGIPEFYDYDVALIKLKNKLKYGQTIRPICLPCTEGTTRALRLPPTTTCQQQKEE → KDATEGPGLHLCSPGNTSHFLQILHSTHPQCSPIPCTPDQSGMGEDVKLGMTRGQRQEAAHKEVVPTLLLQEGRSGTWR
    • 622-764: Missing

Computationally mapped potential isoform sequences

There are 5 potential isoforms mapped to this entry

View all
EntryEntry nameGene nameLength
F8WBL9F8WBL9_HUMANCFB86
H7C5H1H7C5H1_HUMANCFB692
A0A8V8TNU0A0A8V8TNU0_HUMANCFB687
A0A8V8TMI9A0A8V8TMI9_HUMANCFB483
A0A0G2JH38A0A0G2JH38_HUMANCFB589

Features

Showing features for sequence conflict, alternative sequence.

TypeIDPosition(s)Description
Sequence conflict297in Ref. 13; AA sequence
Sequence conflict300in Ref. 12; AAA36225
Sequence conflict328in Ref. 12; AAA36225
Sequence conflict356-357in Ref. 12; AAA36225
Sequence conflict537in Ref. 15; AAA36219
Alternative sequenceVSP_005380543-621in isoform 2
Alternative sequenceVSP_005381622-764in isoform 2
Sequence conflict764in Ref. 15; AAA36220

Polymorphism

Two major variants, F and S, and 2 minor variants, as well as at least 14 very rare variants, have been identified.

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
X72875
EMBL· GenBank· DDBJ
CAA51389.1
EMBL· GenBank· DDBJ
mRNA
S67310
EMBL· GenBank· DDBJ
AAD13989.1
EMBL· GenBank· DDBJ
mRNA
L15702
EMBL· GenBank· DDBJ
AAA16820.1
EMBL· GenBank· DDBJ
mRNA
X00284
EMBL· GenBank· DDBJ
CAA25077.1
EMBL· GenBank· DDBJ
mRNA
AF349679
EMBL· GenBank· DDBJ
AAK30167.1
EMBL· GenBank· DDBJ
mRNA
AF019413
EMBL· GenBank· DDBJ
AAB67977.1
EMBL· GenBank· DDBJ
Genomic DNA
AF551848
EMBL· GenBank· DDBJ
AAN71991.1
EMBL· GenBank· DDBJ
Genomic DNA
AL662849
EMBL· GenBank· DDBJ
-Genomic DNA No translation available.
AL844853
EMBL· GenBank· DDBJ
-Genomic DNA No translation available.
BX005143
EMBL· GenBank· DDBJ
-Genomic DNA No translation available.
CR388219
EMBL· GenBank· DDBJ
-Genomic DNA No translation available.
CR759782
EMBL· GenBank· DDBJ
-Genomic DNA No translation available.
AK223400
EMBL· GenBank· DDBJ
BAD97120.1
EMBL· GenBank· DDBJ
mRNA
AL645922
EMBL· GenBank· DDBJ
-Genomic DNA No translation available.
CH471081
EMBL· GenBank· DDBJ
EAX03550.1
EMBL· GenBank· DDBJ
Genomic DNA
BC004143
EMBL· GenBank· DDBJ
AAH04143.1
EMBL· GenBank· DDBJ
mRNA
BC007990
EMBL· GenBank· DDBJ
AAH07990.1
EMBL· GenBank· DDBJ
mRNA
K01566
EMBL· GenBank· DDBJ
AAA36225.2
EMBL· GenBank· DDBJ
mRNA
J00125
EMBL· GenBank· DDBJ
-Genomic DNA No translation available.
J00126
EMBL· GenBank· DDBJ
AAA36226.1
EMBL· GenBank· DDBJ
mRNA
J00185
EMBL· GenBank· DDBJ
AAA36219.1
EMBL· GenBank· DDBJ
mRNA Sequence problems.
J00186
EMBL· GenBank· DDBJ
AAA36220.1
EMBL· GenBank· DDBJ
mRNA
M15082
EMBL· GenBank· DDBJ
AAA59625.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care. Our staff consists of biologists and biochemists that are not trained to give medical advice.
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