[CEACAM1 as a central modulator of metabolism, tumor progression, angiogenesis and immunity]

CEACAM1 (carcinoembryonic antigen cell adhesion molecule 1), a member of the immunoglobulin (Ig) superfamily, is a heavily glycosylated protein. This glycoprotein exhibits an intracytoplasmic region that can be either long (71-73 amino acids) with two inhibitory tyrosine-phosphorylated motifs and several phosphorylated serine residues, or short (10 amino acid). CEACAM1 is a multifunctional protein that plays a role in intercellular adhesion, as an inhibitor of tumor development, as a bacterial adhesin, and as a receptor for the mouse hepatitis virus. Moreover, CEACAM1 is an active regulator of cell signaling, modulating the insulin or EGF receptor pathways in epithelial cells or the Zap-70 pathway in hematopoietic cells. The recent development of genetically modified mouse models altering the Ceacam1 gene corroborates most of these data, but also highlights CEACAM1's functional complexity. Thus, in addition to the functions identified previously, CEACAM1 is an important regulator of lipid metabolism, of tumor progression as a regulator of the Wnt signaling pathway, of normal and tumor neo-angiogenesis and of immunity.