Description
Natural killer (NK) cells express both activating and inhibitory cell surface receptors. Inhibitory signaling receptors all possess cytoplasmic immunoreceptor tyrosine-based inhibitory motifs, or ITIMs, whereas the activating receptors lack ITIMs and associate with DAP12, which contains an immunoreceptor tyrosine-based activation motif, or ITAM. Killer cell immunoglobulin (Ig)-like receptors, or KIRs, and other NK cell receptors interact with major histocompatibility complex (MHC) molecules. Members of the CD2 family adhere to each other instead. The cell surface glycoprotein 2B4 is related to CD2 and is implicated in the regulation of NK- and T-cell function.
