Q61129 · CFAI_MOUSE

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

Function

function

Trypsin-like serine protease that plays an essential role in regulating the immune response by controlling all complement pathways. Inhibits these pathways by cleaving three peptide bonds in the alpha-chain of C3b and two bonds in the alpha-chain of C4b thereby inactivating these proteins. Essential cofactors for these reactions include factor H and C4BP in the fluid phase and membrane cofactor protein/CD46 and CR1 on cell surfaces. The presence of these cofactors on healthy cells allows degradation of deposited C3b by CFI in order to prevent undesired complement activation, while in apoptotic cells or microbes, the absence of such cofactors leads to C3b-mediated complement activation and subsequent opsonization.

Catalytic activity

  • Inactivates complement subcomponents C3b, iC3b and C4b by proteolytic cleavage.
    EC:3.4.21.45 (UniProtKB | ENZYME | Rhea)

Features

Showing features for binding site, active site.

160350100150200250300350400450500550600
TypeIDPosition(s)Description
Binding site244Ca2+ 1 (UniProtKB | ChEBI)
Binding site247Ca2+ 1 (UniProtKB | ChEBI)
Binding site249Ca2+ 1 (UniProtKB | ChEBI)
Binding site251Ca2+ 1 (UniProtKB | ChEBI)
Binding site257Ca2+ 1 (UniProtKB | ChEBI)
Binding site258Ca2+ 1 (UniProtKB | ChEBI)
Binding site281Ca2+ 2 (UniProtKB | ChEBI)
Binding site284Ca2+ 2 (UniProtKB | ChEBI)
Binding site286Ca2+ 2 (UniProtKB | ChEBI)
Binding site288Ca2+ 2 (UniProtKB | ChEBI)
Binding site294Ca2+ 2 (UniProtKB | ChEBI)
Binding site295Ca2+ 2 (UniProtKB | ChEBI)
Active site401Charge relay system
Active site449Charge relay system
Active site545Charge relay system

GO annotations

AspectTerm
Cellular Componentextracellular space
Cellular Componentmembrane
Molecular Functionmetal ion binding
Molecular Functionserine-type endopeptidase activity
Biological Processcomplement activation
Biological Processcomplement activation, classical pathway
Biological Processinnate immune response
Biological Processproteolysis

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

Gene names

    • Name
      Cfi
    • Synonyms
      If

Organism names

  • Taxonomic identifier
  • Strains
    • BALB/cJ
    • 129/Sv
  • Taxonomic lineage
    Eukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Euarchontoglires > Glires > Rodentia > Myomorpha > Muroidea > Muridae > Murinae > Mus > Mus

Accessions

  • Primary accession
    Q61129
  • Secondary accessions
    • B2RWX8
    • Q9WU07

Proteomes

Organism-specific databases

Subcellular Location

Keywords

Phenotypes & Variants

Disruption phenotype

CFI-deficient mice are viable and fertile under specific pathogen-free conditions. In the absence of factor I/CFI, physiological cleavage of the alpha-chain of C3b is prevented, and reduced plasma C3, factor B, and factor H levels are observed.

Variants

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

The viewer provides 40 variants from UniProt as well as other sources including ClinVar and dbSNP.

Go to variant viewer

PTM/Processing

Features

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

TypeIDPosition(s)Description
Signal1-18
ChainPRO_000002757219-356Complement factor I heavy chain
ChainPRO_000002757119-603Complement factor I
Disulfide bond36↔260
Disulfide bond46↔57
Disulfide bond51↔62
Disulfide bond64↔96
Disulfide bond70↔89
Disulfide bond78↔109
Glycosylation106N-linked (GlcNAc...) asparagine
Glycosylation116N-linked (GlcNAc...) asparagine
Disulfide bond144↔186
Disulfide bond157↔219
Glycosylation174N-linked (GlcNAc...) asparagine
Glycosylation182N-linked (GlcNAc...) asparagine
Disulfide bond191↔201
Disulfide bond234↔252
Disulfide bond246↔261
Disulfide bond264↔276
Glycosylation267N-linked (GlcNAc...) asparagine
Disulfide bond271↔289
Disulfide bond283↔298
Disulfide bond348↔473Interchain (between heavy and light chains)
ChainPRO_0000027573361-603Complement factor I light chain
Disulfide bond386↔402
Disulfide bond394↔464
Disulfide bond473Interchain (with C-327)
Disulfide bond487↔551
Glycosylation514N-linked (GlcNAc...) asparagine
Disulfide bond515↔530
Disulfide bond541↔570
Glycosylation556N-linked (GlcNAc...) asparagine

Keywords

Proteomic databases

PTM databases

Expression

Tissue specificity

Expressed in the liver by hepatocytes. Also present in other cells such as monocytes, fibroblasts or keratinocytes.

Gene expression databases

Interaction

Subunit

Heterodimer of a light and heavy chains; disulfide-linked. The fully processed and mature protein circulates as a zymogen, and is allosterically activated by substrate-induced remodeling of the active site. Interacts with C3b. Interacts with complement factor H.

Protein-protein interaction databases

Miscellaneous

Structure

Family & Domains

Features

Showing features for domain.

TypeIDPosition(s)Description
Domain58-111Kazal-like
Domain117-217SRCR
Domain218-262LDL-receptor class A 1
Domain263-299LDL-receptor class A 2
Domain361-594Peptidase S1

Sequence similarities

Belongs to the peptidase S1 family.

Keywords

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Sequence processing
    The displayed sequence is further processed into a mature form.
  • Length
    603
  • Mass (Da)
    67,261
  • Last updated
    2011-07-27 v3
  • Checksum
    A9B90E1EC78AEE37
MKLAHLSLFLLALHLSSSRSPSASDLPQEELVDQKCLLQKYTHRSCNKVFCQPWQRCIEGTCICKLPYQCPRAGTPVCAMNGRSYPTYCHQKSFECLHPEIKFSHNGTCAAEGKFNVSLIYGRTKTEGLVQVKLVDQDERMFICKNSWSMAEANVACVDLGFPLGVRDIQGSFNISGNLHINDTECLHVHCRGVETSLAECAFTKRRTELSNGLAGVVCYKQDADFPTSLSFQCVNGKHIPQEKACNGVNDCGDQSDELCCKGCRGNASLCKSGVCIPDQYKCNGEVDCITGEDESRCEEDRQQNIPKGLARSAQGEAEIETEETEMLTPGMDNERKRIKSLLPKLSCGVKRNTHTRRKRVIGGKPANVGDYPWQVAIKDGQRITCGGIYIGGCWILTAAHCVRPSRAHSYQVWTALLDWLKPNSQLGIQTVKRVIVHEKYNGATFQNDIALIEMKMHTGKKECELPNSVPACVPWSPYLFQPNDRCIISGWGRGKDNQKVYSLRWGEVDLIGNCSQFYPDRYYEKEMQCAGTRDGSIDACKGDSGGPLVCEDINNVTYVWGIVSWGENCGKPEFPGVYTRVANYFDWISYHVGRSLVSQHNV

Computationally mapped potential isoform sequences

There is 1 potential isoform mapped to this entry

View all
EntryEntry nameGene nameLength
A0A0G2JF07A0A0G2JF07_MOUSECfi145

Features

Showing features for sequence conflict.

TypeIDPosition(s)Description
Sequence conflict114in Ref. 1; AAB00438
Sequence conflict236-252in Ref. 1; AAB00438
Sequence conflict554in Ref. 1; AAB00438

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
U47810
EMBL· GenBank· DDBJ
AAB00438.1
EMBL· GenBank· DDBJ
mRNA
BC150751
EMBL· GenBank· DDBJ
AAI50752.1
EMBL· GenBank· DDBJ
mRNA
AH007741
EMBL· GenBank· DDBJ
AAD32965.1
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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