CD33 Antibody

SIGLEC3/CD33 is a putative adhesion molecule of myelomonocytic-derived cells that mediates sialic-acid dependent binding to cells. It preferentially binds to alpha2,6-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, CD33 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. This protein Induces apoptosis in acute myeloid leukemia (in vitro). It has been shown to interact with PTPN6/SHP-1 and PTPN11/SHP-2 upon phosphorylation. CD333 expresses in monocytic/myeloid lineage cells, and contains 2 copies of a cytoplasmic motif that is referred to as the immunoreceptor tyrosine-based inhibitor motif (ITIM). This motif is involved in downmodulation of cellular responses. The phosphorylated ITIM motif binds to the SH2 domain of PTPN6/SHP-1. Phosphorylation of Tyr-340 is involved in binding to PTPN6 and PTPN11. Phosphorylation of Tyr-358 is involved in binding to PTPN6.