The Siglec Family

MAG (Siglec-4a) is a member of the siglec family of sialic acid (NeuSAc) binding I-type lectins (carbohydrate binding proteins) within the immunoglobulin superfamily IgSF (Table 16.1) [16]. 

Siglec-1 Sn (Sialoadhesin) Macrophages in spleen, lymph nodes, and bone marrow Neu5Ac-a(2-3)-Gal-P(l-3/4)-GlcAAc- Neu5Ac-a(2-3)-Gal-P(l-3)-GaL/VAc- 

Siglec-4a MAG Peripheral and central nerve system Neu5Ac-a(2-3)-Gal-P(l-3)-GaL/VAc- 

Siglec-4b SMP (Schwann cell myelin protein) Schwann cells in quail Neu5Ac-a(2-3)-Gal- 

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Angata T (2006) Molecular diversity and evolution of the Siglec family of cell-surface lectins. Mol Divers 10 555-566... 

Figure 1. Unusual disulfides in the NH2-terminal two domains of members of the siglec family. Three cysteines exist in each of the V-set and adjacent C-2 set domains of siglec family members, resulting in a conserved pattern of inter-sheet, intra-sheet and inter-domain disulfide bonds.

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