NK cell receptors.
NK cells are regulated by opposing signals from receptors that activate and inhibit effector function. While positive stimulation may be initiated by an array of costimulatory receptors, specificity is provided by inhibitory signals transduced by receptors for MHC class I. Three distinct receptor families, Ly49, CD94/NKG2, and KIR, are involved in NK cell recognition of polymorphic MHC class I molecules. A common pathway of inhibitory signaling is provided by ITIM sequences in the cytoplasmic domains of these otherwise structurally diverse receptors. Upon ligand binding and activation, the inhibitory NK cell receptors become tyrosine phosphorylated and recruit tyrosine phosphatases, SHP-1 and possibly SHP-2, resulting in inhibition of NK cell-mediated cytotoxicity and cytokine expression. Recent studies suggest these inhibitory NK cell receptors are members of a larger superfamily containing ITIM sequences, the inhibitory receptor superfamily (IRS).
Lanier
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DNAX Research Institute of Molecular and Cellular Biology, Palo Alto, California 94304, USA. lanier@dnax.org
D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D000950:Antigens, Ly; D000954:Antigens, Surface / Q000502:physiology; D003602:Cytotoxicity, Immunologic; D019204:GTP-Binding Proteins / Q000502:physiology; D006801:Humans; D017874:Immediate-Early Proteins / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D007694:Killer Cells, Natural / Q000502:physiology*; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins / Q000502:physiology; D020559:Monomeric GTP-Binding Proteins; D051920:NK Cell Lectin-Like Receptor Subfamily D; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000502:physiology; D011971:Receptors, Immunologic / Q000502:physiology*; D055630:Receptors, NK Cell Lectin-Like; D015398:Signal Transduction / Q000502:physiology; D001613:beta 2-Microglobulin / Q000502:physiology
D015703:Antigens, CD; D000950:Antigens, Ly; D000954:Antigens, Surface; D017874:Immediate-Early Proteins; D047908:Intracellular Signaling Peptides and Proteins; C497869:KLRD1 protein, human; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D051920:NK Cell Lectin-Like Receptor Subfamily D; D011971:Receptors, Immunologic; D055630:Receptors, NK Cell Lectin-Like; D001613:beta 2-Microglobulin; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D019204:GTP-Binding Proteins; C490245:GEM protein, human; D020559:Monomeric GTP-Binding Proteins