CEACAM1/CD66a [E1]

CEACAM1 (also known as C-CAM and CD66a) is a member of CEA-related cell-adhesion molecule (CEACAM) subfamily of the carcinoembryonic antigen (CEA) family. CEACAM1 is expressed by certain epithelial, endothelial, lymphoid, and myeloid cells. Human CEACAM1 has many different splice variants; the abundance of CEACAM1 and the relative ratio of the different isoforms varies markedly among cell types and may be regulated in a context-dependent fashion. The isoforms with long (L) and short (S) cytoplasmic tails have different signaling properties. Notably, L isoforms contain a functional ITIM (immunoreceptor tyrosine-based inhibitory motif) and several serine and threonine residues that could serve as potential phosphorylation targets. The extracellular domain of CEACAM1 is heavily glycosylated, making its apparent molecular weight during electrophoresis much larger than its predicted size (57.6 kDa). CEACAM1 mediates intercellular adhesion through homo- and heterophilic interaction with other members of the CEACAM family. Studies indicate that CEACAM1 plays important roles in angiogenesis, neovascularization, insulin signaling, T cell signaling, and tumorigenesis. In addition, CEACAM1 can function as a receptor for several microbial pathogens.