Complement FACTOR I (CFI) Antibody – Monoclonal

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 uraemic syndrome, a disease characterized by acute renal failure, microangiopathic hemolytic anemia and thrombocytopenia. Primary glomerulonephritis with immmune deposits is another condition associated with mutation of this gene. [provided by RefSeq, Jul 2008]

CFI: Responsible for cleaving the alpha-chains of C4b and C3b in the presence of the cofactors C4-binding protein and factor H respectively. Defects in CFI are a cause of susceptibility to hemolytic uremic syndrome atypical type 3 (AHUS3). 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. 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. Defects in CFI are the cause of complement factor I deficiency (CFI deficiency). CFI deficiency is an autosomal recessive condition associated with a propensity to pyogenic infections. Belongs to the peptidase S1 family.

Protein type: Secreted; Protease; EC 3.4.21.45; Secreted, signal peptide

Chromosomal Location of Human Ortholog: 4q25

Cellular Component: extracellular space; membrane; extracellular region; nucleus

Molecular Function: serine-type endopeptidase activity; metal ion binding; scavenger receptor activity

Biological Process: receptor-mediated endocytosis; regulation of complement activation; innate immune response; proteolysis; complement activation, classical pathway

Disease: Macular Degeneration, Age-related, 13; Complement Factor I Deficiency; Hemolytic Uremic Syndrome, Atypical, Susceptibility To, 3