Signaling pathways engaged by NK cell receptors: double concerto for activating receptors, inhibitory receptors and NK cells

Semin Immunol. 2000 Apr;12(2):139-47. doi: 10.1006/smim.2000.0216.


Despite the absence of antigen-specific receptors at their surface, NK cells can selectively eliminate virus-infected cells, tumor cells and allogenic cells. A dynamic and precisely coordinated balance between activating and inhibitory receptors governs NK cell activation programs. Multiple activating and inhibitory NK cell surface molecules have been described, a group of them acting as receptors for MHC class I molecules. In spite of their heterogeneity, activating NK cell receptors present remarkable structural and functional homologies with T cell- and B cell-antigen receptors. Inhibitory NK cell receptors operate at early stages of activating cascades by recruiting protein tyrosine phosphatases via intra- cytoplasmic motifs (ITIM), a strategy which is widely conserved in hematopoietic and non-hematopoietic cells.

Publication types

  • Review

MeSH terms

  • Cytotoxicity, Immunologic*
  • Immunosuppressive Agents / metabolism
  • Killer Cells, Natural / immunology*
  • Models, Immunological
  • Receptors, Immunologic / metabolism*
  • Signal Transduction


  • Immunosuppressive Agents
  • Receptors, Immunologic