Source: hRBCD ; ID: IPI00216550
BGMUT ; ID: cromer
Marked as 'Membrane associated protein'
Confidence: high (a blood group or CD marker) Search PubMed for
(RBC AND this entry)

Gene names: CD55 , CR, DAF
Protein names and data: DAF_HUMAN , Complement decay-accelerating factor , CD55; Flags: Precursor Lenght: 381 a.a.
Mass: 41400 Da
fasta formatted sequence

Function: This protein recognizes C4b and C3b fragments that condense with cell-surface hydroxyl or amino groups when nascent C4b and C3b are locally generated during C4 and c3 activation. Interaction of daf with cell-associated C4b and C3b polypeptides interferes with their ability to catalyze the conversion of C2 and factor B to enzymatically active C2a and Bb and thereby prevents the formation of C4b2a and C3bBb, the amplification convertases of the complement cascade.
Cellular location: Isoform 1: Cell membrane; Single-pass type I membrane protein. Isoform 2: Cell membrane; Lipid-anchor, GPI- anchor. Isoform 3: Secreted. Isoform 4: Secreted. Isoform 5: Secreted. Isoform 6: Cell membrane; Lipid-anchor, GPI- anchor (Probable). Isoform 7: Cell membrane; Lipid-anchor, GPI- anchor (Probable).
Tissue specificity: Expressed on the plasma membranes of all cell types that are in intimate contact with plasma complement proteins. It is also found on the surfaces of epithelial cells lining extracellular compartments, and variants of the molecule are present in body fluids and in extracellular matrix.

Genetic variants

Responsible for the Cromer blood group system (CROM) [MIM:613793]. It consists of at least 8 high-incidence (Cr(a), Tc(a), Dr(a), Es(a), WES(b), UMC, IFC and GUTI) and three low- incidence (Tc(b), Tc(c) and WES(a)) antigens that reside on DAF. In the Cromer phenotypes Dr(a-) and Inab there is reduced or absent expression of DAF, respectively. In the case of the Dr(a-) phenotype, a single nucleotide substitution within exon 5 accounts for two changes: a simple amino acid substitution, Leu-199 that is the basis of the antigenic variation, and an alternative splicing event that underlies the decreased expression of DAF in this phenotype. The Inab phenotype is a very rare one in which the red blood cells lack all Cromer system antigens. The red blood cells of individuals with Inab phenotype have a deficiency of DAF, but these individuals are not known to have any associated hematologic or other abnormalities.

Database cross-references

UniProt: P08174
Ensembl: ENST00000314754
Ensembl: ENST00000367062
Ensembl: ENST00000367064
Ensembl: ENST00000367065
Ensembl: ENST00000391920
MIM: 125240
MIM: 613793
neXtProt: NX_P08174
Antibodypedia: P08174 (may not find the protein thus also not any antibody)
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