Granulocyte orphan receptor that acts as an trigger efficient phagocytosis of attached particles. Interacts through its phosphorylated ITAM domain with the SH2 domain-containing cytoplasmic proteins involved in signaling processes during phagocytosis. Granulocytes. N-glycosylated. The cytoplasmic ITAM-like sequence becomes tyrosine phosphorylated by SRC family PTKs upon ligand-mediated receptor clustering and allows to initiate phagocytosis of bound ligand. To study the function of the orphan receptor CEACAM4 chimeric proteins containing the extracellular bacteria-binding domain of CEACAM3 and the transmembrane and cytoplasmic part of CEACAM4 has been used. Belongs to the immunoglobulin superfamily. CEA family.