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Letter

Nature Chemical Biology 1, 93–97 (1 July 2005) | doi:10.1038/nchembio713

Homomultimeric complexes of CD22 in B cells revealed by protein-glycan cross-linking

Shoufa Han , Brian E Collins , Per Bengtson & James C Paulson

CD22 is a negative regulator of B-cell receptor signaling, an activity mediated by recruitment of SH2 domain–containing phosphatase 1 through a phosphorylated immunoreceptor tyrosine inhibitory motif in its cytoplasmic domain. As in other members of the sialic acid–binding immunoglobulin-like lectin, or siglec, family, the extracellular N-terminal immunoglobulin domain of CD22 binds to glycan ligands containing sialic acid, which are highly expressed on B-cell glycoproteins.