Putative adhesion molecule that mediates sialic-acid dependent binding to cells. Preferentially binds to alpha-2,8-linked sialic acid. The sialic acid recognition site may be masked by cis interactions with sialic acids on the same cell surface. In the immune response, may act as an inhibitory receptor upon ligand induced tyrosine phosphorylation by recruiting cytoplasmic phosphatase(s) via their SH2 domain(s) that block signal transduction through dephosphorylation of signaling molecules. Interacts with PTPN6/SHP-1 and PTPN11/SHP-2 upon phosphorylation. Expressed by macrophages in various tissues including Kupffer cells. Also found in brain microglia. Contains 1 copy of a cytoplasmic motif that is referred to as the immunoreceptor tyrosine-based inhibitor motif (ITIM). This motif is involved in modulation of cellular responses. The phosphorylated ITIM motif can bind the SH2 domain of several SH2-containing phosphatases. Phosphorylated on tyrosine residues. Belongs to the immunoglobulin superfamily. SIGLEC (sialic acid binding Ig-like lectin) family. It is uncertain whether Met-1 or Met-13 is the initiator. Truncated N-terminus. Truncated N-terminus.