Complement receptor 2

CR2
Available structures
PDB	Ortholog search: PDBe RCSB
List of PDB id codes
	1GHQ, 1LY2, 1W2R, 1W2S, 2GSX, 3OED
Identifiers
Aliases	CR2, C3DR, CD21, CR, CVID7, SLEB9, complement component 3d receptor 2, complement C3d receptor 2
External IDs	OMIM: 120650; MGI: 88489; HomoloGene: 55611; GeneCards: CR2; OMA:CR2 - orthologs
Gene location (Human)
Chr.	Chromosome 1 (human)
End	207,489,895 bp
Gene location (Mouse)
Chr.	Chromosome 1 (mouse)
End	194,859,024 bp
RNA expression pattern
	Top expressed in
	secondary oocyte; ; spleen; ; appendix; ; lymph node; ; mucosa of ileum; ; epithelium of nasopharynx; ; tonsil; ; superficial temporal artery; ; testicle; ; rectum;
	Top expressed in
	spleen; ; mesenteric lymph nodes; ; blood; ; subcutaneous adipose tissue; ; neural layer of retina; ; spermatid; ; tunica media of zone of aorta; ; embryo; ; tunica adventitia of aorta; ; embryo;
	More reference expression data
	More reference expression data
Gene ontology
Molecular function	DNA binding; protein homodimerization activity; virus receptor activity; complement binding; transmembrane signaling receptor activity; complement receptor activity; protein binding;
Cellular component	integral component of membrane; membrane; receptor complex; extracellular exosome; plasma membrane;
Biological process	immune system process; B cell proliferation; immune response; complement activation, classical pathway; viral entry into host cell; B cell differentiation; innate immune response; viral process; complement receptor mediated signaling pathway; signal transduction; regulation of complement activation;
	Sources:Amigo / QuickGO
Orthologs
	1380
	12902
	ENSG00000117322
	ENSMUSG00000026616
	P20023
	P19070
	NM_001006658; NM_001877
	NM_007758; NM_001368765
	NP_001006659; NP_001868
	n/a
	Wikidata
View/Edit Human	View/Edit Mouse

Complement receptor type 2 (CR2), also known as complement C3d receptor, Epstein–Barr virus receptor, and CD21 (cluster of differentiation 21), is a protein that in humans is encoded by the CR2 gene.

CR2 is involved in the complement system. It binds to iC3b (inactive derivative of C3b), C3dg, or C3d. B cells express CR2 on their surfaces, allowing the complement system to play a role in B-cell activation and maturation.