Figure 2.

Schematic representation of key activating receptors of natural killer cells, their intracellular domains, and their respective tumor antigens. CD16 binds to the Fc region of IgG monoclonal antibodies that are bound to tumor antigens, initiating the antibody-dependent cellular cytotoxicity function of NK cells. The receptors CD16, NKp30, and NKp46 signal through the phosphorylation of immunoreceptor tyrosine-based motifs (ITAMs) within their associated intracellular domains, CD3ζ and FcεRIγ, mediated by Zap70 and Syk kinases. Similarly, NKp44 transmits signals through the phosphorylation of ITAMs of DAP12 by Zap70 and Syk kinases. The receptor NKG2D signals via two DAP10 intracellular domains, which employ tyrosine–isoleucine–asparagine–methionine (YINM) that is phosphorylated by phosphoinositide 3-kinase (PI3K). Created with Biorender.