NCR1, also known as NK-p46 and CD335, is a natural cytotoxicity receptor(NCR). NCRs are type I transmembrane proteins with 1-2 extracellular immunoglobulin domains, a transmembrane domain containing a positively charged amino acid residue, and a short cytoplasmic tail. All are expressed almost exclusively by NK cells and play a major role in triggering NK-mediated killing of most tumor cell lines. NKp46 has two extracellular Ig-like domains followed by a ~40 residue stalk region, a type I transmembrane domain, and a short cytoplasmic tail. NKp46 has been implicated in NK cell-mediated lysis of several autologous tumor cells, pathogen-infected cell lines, and mononuclear phagocytes infected with an intracellular bacterium.