CD66a
CD66a is CEACAM1, the biliary glycoprotein and founding member of the carcinoembryonic antigen family, encoded by the CEACAM1 gene. It carries an N-terminal Ig V-like domain plus Ig C2-like domains and occurs in isoforms with long or short cytoplasmic tails. CEACAM1 mediates homophilic and heterophilic adhesion, and the long-tail isoform contains ITIM motifs that deliver inhibitory signals in neutrophils and epithelial cells. It serves as a receptor for Opa proteins of Neisseria species and for certain other bacterial and viral pathogens. CEACAM1 behaves as a tumor suppressor in several carcinomas, modulates insulin sensitivity, and supports vascular and immune homeostasis.
