Regulation through inhibitory receptors: Lessons from natural killer cells

Trends Cell Biol. 1997 Dec;7(12):473-9. doi: 10.1016/S0962-8924(97)01167-7.


Natural killer (NK) cells employ an unconventional mode of recognition: they kill target cells that lack ligands for inhibitory NK cell receptors. Activation of NK cytotoxicity is tightly controlled by inhibitory receptors that recruit and activate the tyrosine phosphatase SHP-1 through the tyrosine-phosphorylated [I/V]xYxxL amino acid sequence in their cytoplasmic tail. This sequence motif, often referred to as an immunoreceptor tyrosine-based inhibitory motif (ITIM), is found in several other receptors that deliver similar negative signals in diverse types of cells. We suggest that this kind of regulation through inhibition is a widespread mechanism for the control of various cellular responses.