SLAM family member 7 (SLAMF7), also known as CRACC, CD319, CD2-like receptor-activating cytotoxic cells, and CS1, is a single-pass type I membrane protein and a member of the CD2 family of cell surface receptors. SLAMF7 is expressed on the surface of NK cells, CD8+ T cells, activated B cells, and mature dendritic cells but not in promyelocytic, B-cell lines, or T-cell lines. In human NK cells, activated SLAMF7 transmits signals following association with the adaptor protein EAT-2 . In the absence of EAT-2, SLAMF7 potently inhibited natural killer cell function. It was also inhibitory in T cells, which are typically devoid of EAT-2. Thus, SLAMF7 can exert activating or inhibitory influences on cells of the immune system depending on cellular context and the availability of effector proteins.