CD22

CD22
Identifiers
Aliases	CD22, SIGLEC-2, SIGLEC2, CD22 molecule
External IDs	OMIM: 107266; MGI: 88322; HomoloGene: 31052; GeneCards: CD22; OMA:CD22 - orthologs
Gene location (Mouse)
Chr.	Chromosome 7 (mouse)
End	30,579,767 bp
RNA expression pattern
	Top expressed in
	spleen; ; appendix; ; lymph node; ; right uterine tube; ; sural nerve; ; corpus callosum; ; putamen; ; inferior olivary nucleus; ; caudate nucleus; ; amygdala;
	Top expressed in
	spleen; ; mesenteric lymph nodes; ; blood; ; tibiofemoral joint; ; subcutaneous adipose tissue; ; submandibular gland; ; granulocyte; ; calvaria; ; morula; ; tunica adventitia of aorta;
	More reference expression data
	; ; ; ;
	More reference expression data
Gene ontology
Molecular function	protein binding; carbohydrate binding; IgM binding; signaling receptor binding; protein phosphatase binding; sialic acid binding; CD4 receptor binding;
Cellular component	integral component of membrane; plasma membrane; extracellular exosome; membrane; cytoplasm; early endosome; cell surface; neuronal cell body membrane; recycling endosome;
Biological process	cell adhesion; regulation of endocytosis; regulation of B cell proliferation; B cell activation; regulation of immune response; negative regulation of calcium-mediated signaling; negative regulation of B cell receptor signaling pathway;
	Sources:Amigo / QuickGO
Orthologs
	933
	12483
	n/a
	ENSMUSG00000030577
	P20273
	P35329
NM_024916; NM_001185099; NM_001185100; NM_001185101; NM_001278417;
	NM_001771
	NM_001043317; NM_009845
	NP_001172028; NP_001172029; NP_001172030; NP_001265346; NP_001762
	NP_001036782; NP_033975
	Wikidata
View/Edit Human	View/Edit Mouse

CD22, or cluster of differentiation-22, is a molecule belonging to the SIGLEC family of lectins.^[4] It is found on the surface of mature B cells and to a lesser extent on some immature B cells. Generally speaking, CD22 is a regulatory molecule that prevents the overactivation of the immune system and the development of autoimmune diseases.^[5]

CD22 is a sugar binding transmembrane protein, which specifically binds sialic acid with an immunoglobulin (Ig) domain located at its N-terminus. The presence of Ig domains makes CD22 a member of the immunoglobulin superfamily. CD22 functions as an inhibitory receptor for B cell receptor (BCR) signaling. It is also involved in the B cell trafficking to Peyer's patches in mice.^[6] In mice, it has been shown that CD22 blockade restores homeostatic microglial phagocytosis in aging brains.^[7]

^ ^a ^b ^c GRCm38: Ensembl release 89: ENSMUSG00000030577 – Ensembl, May 2017
^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
^ Crocker PR, Clark EA, Filbin M, Gordon S, Jones Y, Kehrl JH, et al. (February 1998). "Siglecs: a family of sialic-acid binding lectins". Glycobiology. 8 (2): v. doi:10.1093/oxfordjournals.glycob.a018832. PMID 9498912.
^ Hatta Y, Tsuchiya N, Matsushita M, Shiota M, Hagiwara K, Tokunaga K (April 1999). "Identification of the gene variations in human CD22". Immunogenetics. 49 (4): 280–286. doi:10.1007/s002510050494. PMID 10079291. S2CID 22947237.
^ Lee M, Kiefel H, LaJevic MD, Macauley MS, Kawashima H, O'Hara E, et al. (October 2014). "Transcriptional programs of lymphoid tissue capillary and high endothelium reveal control mechanisms for lymphocyte homing". Nature Immunology. 15 (10): 982–995. doi:10.1038/ni.2983. PMC 4222088. PMID 25173345.
^ Pluvinage JV, Haney MS, Smith BA, Sun J, Iram T, Bonanno L, et al. (April 2019). "CD22 blockade restores homeostatic microglial phagocytosis in ageing brains". Nature. 568 (7751): 187–192. Bibcode:2019Natur.568..187P. doi:10.1038/s41586-019-1088-4. PMC 6574119. PMID 30944478.

[refGRCm38Ensembl-1] GRCm38: Ensembl release 89: ENSMUSG00000030577 – Ensembl, May 2017

[2] "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[3] "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.

[pmid9498912-4] Crocker PR, Clark EA, Filbin M, Gordon S, Jones Y, Kehrl JH, et al. (February 1998). "Siglecs: a family of sialic-acid binding lectins". Glycobiology. 8 (2): v. doi:10.1093/oxfordjournals.glycob.a018832. PMID 9498912.

[Hatta1999-5] Hatta Y, Tsuchiya N, Matsushita M, Shiota M, Hagiwara K, Tokunaga K (April 1999). "Identification of the gene variations in human CD22". Immunogenetics. 49 (4): 280–286. doi:10.1007/s002510050494. PMID 10079291. S2CID 22947237.

[6] Lee M, Kiefel H, LaJevic MD, Macauley MS, Kawashima H, O'Hara E, et al. (October 2014). "Transcriptional programs of lymphoid tissue capillary and high endothelium reveal control mechanisms for lymphocyte homing". Nature Immunology. 15 (10): 982–995. doi:10.1038/ni.2983. PMC 4222088. PMID 25173345.

[J.V._Pluvinage_et_al.-7] Pluvinage JV, Haney MS, Smith BA, Sun J, Iram T, Bonanno L, et al. (April 2019). "CD22 blockade restores homeostatic microglial phagocytosis in ageing brains". Nature. 568 (7751): 187–192. Bibcode:2019Natur.568..187P. doi:10.1038/s41586-019-1088-4. PMC 6574119. PMID 30944478.

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