Recombinant Human Complement factor I (CFI)

Uniprot Id

P05156

Target Species

Human

Target Name

CFI

Target Full Name

Complement factor I

Target 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.

Target Involvement

Hemolytic uremic syndrome atypical 3 (AHUS3); Complement factor I deficiency (CFI deficiency); Macular degeneration, age-related, 13 (ARMD13)

Target Subcellular Location

Secreted, extracellular space. Secreted.

Target Protein Families

Peptidase S1 family

Target Tissue Specificity

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

Target Research Area

Immunology

Target Synonyms

AHUS3; ARMD13; C3b INA; C3b inactivator ; C3B/C4B inactivator; C3BINA; CFAI_HUMAN; Cfi; Complement component I; Complement control protein factor I; Complement factor I; Complement factor I heavy chain; Complement factor I light chain; F1; factor I ; FactorI; FI; I factor; IF; KAF; Konglutinogen activating factor; Light chain of factor I ; OTTHUMP00000219728; OTTHUMP00000221928

Target Background

This gene encodes a serine proteinase that is essential for regulating the complement cascade. The encoded preproprotein is cleaved to produce both heavy and light chains, which are linked by disulfide bonds to form a heterodimeric glycoprotein. This heterodimer can cleave and inactivate the complement components C4b and C3b, and it prevents the assembly of the C3 and C5 convertase enzymes. Defects in this gene cause complement factor I deficiency, an autosomal recessive disease associated with a susceptibility to pyogenic infections. Mutations in this gene have been associated with a predisposition to atypical hemolytic uremic syndrome, a disease characterized by acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia. Primary glomerulonephritis with immune deposits and age-related macular degeneration are other conditions associated with mutations of this gene.