Source: hRBCD ; ID: IPI00018287
BGMUT ; ID: knops
Marked as 'Integral membrane protein'
Confidence: high (a blood group or CD marker) Search PubMed for
(RBC AND this entry)

Gene names: CR1 , C3BR
Protein names and data: CR1_HUMAN , Complement receptor type 1 , C3b/C4b receptor; CD35; Flags: Precursor Lenght: 2039 a.a.
Mass: 223663 Da
fasta formatted sequence

Function: Mediates cellular binding of particles and immune complexes that have activated complement.
Cellular location: Membrane; Single-pass type I membrane protein.
Tissue specificity: Present on erythrocytes, leukocytes, glomerular podocytes, and splenic follicular dendritic cells.

Genetic variants

CR1 contains a system of antigens called the Knops blood group system. Polymorphisms within this system are involved in malarial rosetting, a process associated with cerebral malaria, the major cause of mortality in Plasmodium falciparum malaria. Common Knops system antigens include McCoy (McC) and Sl(a)/Vil (Kn4, or Swain-Langley; Vil or Villien). Sl(a-) phenotype is more common in persons of African descent and may protect against fatal malaria. Other polymorphic forms of CR1 contain 23, 37 or 44 Sushi (CCP/SCR) domains instead of the 30 Sushi (CCP/SCR) domains. The most frequent alleles are the F allotype (shown here) and the S allotype (37 repeat Sushi domains). The gene frequencies of the F allotype and S allotype are 0.87 and 0.11 in Caucasians, 0.82 and 0.11 in African Americans, 0.89 and 0.11 in Mexicans. Genetic variations in CR1 resulting in CR1 deficiency are involved in protection against severe malaria [MIM:611162]. Parasitized red blood cells (RBCs) from children suffering from severe malaria often adhere to complement receptor 1 (CR1) on uninfected RBCs to form clumps of cells known as rosettes. CR1-deficient red blood cells show greatly reduced rosetting and CR1 deficiency occurs in healthy individuals from malaria-endemic regions.

Database cross-references

UniProt: P17927
Ensembl: ENST00000367051
Ensembl: ENST00000367053
Ensembl: ENST00000400960
MIM: 120620
MIM: 607486
MIM: 611162
neXtProt: NX_P17927
Antibodypedia: P17927 (may not find the protein thus also not any antibody)
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