This gene encodes a carcinoma-associated antigen and is a member of a family that includes at least two type I membrane proteins.This antigen is expressed on most normal epithelial cells and gastrointestinal carcinomas and functions as a homotypic calcium-independent cell adhesion molecule. The antigen is being used as a target for immunotherapy treatment of human carcinomas. Mutations inThis gene result in congenital tufting enteropathy. [provided by RefSeq, Dec 2008]
show all
Function:
Domain:Contains 2 copies 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.,Putative adhesion molecule of myelomonocytic-derived cells that mediates sialic-acid dependent binding to cells. Preferentially binds to alpha-2,6-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, 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. Induces apoptosis in acute myeloid leukemia (in vitro).,online information:Siglec-3,PTM:Phosphorylation of Tyr-340 is involved in binding to PTPN6 and PTPN11. Phosphorylation of Tyr-358 is involved in binding to PTPN6.,similarity:Belongs to the immunoglobulin superfamily. SIGLEC (sialic acid binding Ig-like lectin) family.,similarity:Contains 1 Ig-like C2-type (immunoglobulin-like) domain.,similarity:Contains 1 Ig-like V-type (immunoglobulin-like) domain.,subunit:Interacts with PTPN6/SHP-1 and PTPN11/SHP-2 upon phosphorylation.,tissue specificity:Monocytic/myeloid lineage cells.,
show all
Cellular Localization:
Lateral cell membrane ; Single-pass type I membrane protein . Cell junction, tight junction . Colocalizes with CLDN7 at the lateral cell membrane and tight junction. .
show all
Tissue Expression:
Monocytic/myeloid lineage cells. In the brain, CD33 is mainly expressed on microglial cells.