Reactome | CD22 mediated BCR regulation

CD22 mediated BCR regulation

Stable Identifier

R-HSA-5690714

DOI

10.3180/r-hsa-5690714.1

Type

Pathway

Species

Homo sapiens

ReviewStatus

5/5

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BCR activation is highly regulated and coreceptors like CD22 (SIGLEC2) set a signalling threshold to prevent aberrant immune response and autoimmune disease (Cyster et al. 1997, Han et al. 2005). CD22 is a glycoprotein found on the surface of B cells during restricted stages of development. CD22 is a member of the receptors of the sialic acid-binding Ig-like lectin (Siglec) family which binds specifically to the terminal sequence N-acetylneuraminic acid alpha(2-6) galactose (NeuAc-alpha(2-6)-Gal) present on many B-cell glycoproteins (Powell et al. 1993, Sgroi et al. 1993). CD22 has seven immunoglobulin (Ig)-like extracellular domains and a cytoplasmic tail containing six tyrosines, three of which belong to the inhibitory immunoreceptor tyrosine-based inhibition motifs (ITIMs) sequences. Upon BCR cross-linking CD22 is rapidly tyrosine phosphorylated by the tyrosine kinase Lyn, thereby recruiting and activating tyrosine phosphatase, SHP-1 and inhibiting calcium signalling.

Literature References

PubMed ID	Title	Journal	Year
15378059	CD22 regulates B lymphocyte function in vivo through both ligand-dependent and ligand-independent mechanisms Tedder, TF, Haas, KM, Fujimoto, M, Miller, AS, Poe, JC, Sanford, IG, Fujimoto, Y, Hasegawa, M, Bock, CB	Nat. Immunol.	2004
22566885	Regulation of B cell functions by the sialic acid-binding receptors siglec-G and CD22 Jellusova, J, Nitschke, L	Front Immunol	2011