Structure and function of natural killer cell surface receptors.
Since mid-1990, with cloning and identification of several families of natural killer (NK) receptors, research on NK cells began to receive appreciable attention. Determination of structures of NK cell surface receptors and their ligand complexes led to a fast growth in our understanding of the activation and ligand recognition by these receptors as well as their function in innate immunity. Functionally, NK cell surface receptors are divided into two groups, the inhibitory and the activating receptors. Structurally, they belong to either the immunoglobulin (Ig)-like receptor superfamily or the C-type lectin-like receptor (CTLR) superfamily. Their ligands are either members of class I major histocompatibility complexes (MHC) or homologs of class I MHC molecules. The inhibitory form of NK receptors provides the protective immunity through recognizing class I MHC molecules with self-peptides on healthy host cells. The activating, or the noninhibitory, NK receptors mediate the killing of tumor or virally infected cells through their specific ligand recognition. The structures of activating and inhibitory NK cell surface receptors and their complexes with the ligands determined to date, including killer immunoglobulin-like receptors (KIRs) and their complexes with HLA molecules, CD94, Ly49A, and its complex with H-2Dd, and NKG2D receptors and their complexes with class I MHC homologs, are reviewed here.
Radaev
Sergei
S
Structural Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA. sradaev@niaid.nih.gov
Sun
Peter D
PD
D000936:Antigen-Antibody Complex / Q000737:chemistry / Q000276:immunology; D015703:Antigens, CD / Q000737:chemistry / Q000276:immunology; D000950:Antigens, Ly / Q000737:chemistry / Q000276:immunology; D006680:HLA Antigens / Q000737:chemistry / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000737:chemistry* / Q000276:immunology; D007694:Killer Cells, Natural / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D037181:Lectins, C-Type / Q000737:chemistry / Q000276:immunology; D046911:Macromolecular Substances; D008958:Models, Molecular; D051920:NK Cell Lectin-Like Receptor Subfamily D; D011485:Protein Binding; D011487:Protein Conformation; D011971:Receptors, Immunologic / Q000737:chemistry* / Q000276:immunology; D054340:Receptors, KIR; D055630:Receptors, NK Cell Lectin-Like; D055607:Receptors, Natural Killer Cell; D013329:Structure-Activity Relationship
D000936:Antigen-Antibody Complex; D015703:Antigens, CD; D000950:Antigens, Ly; D006680:HLA Antigens; D015395:Histocompatibility Antigens Class I; D037181:Lectins, C-Type; D046911:Macromolecular Substances; D051920:NK Cell Lectin-Like Receptor Subfamily D; D011971:Receptors, Immunologic; D054340:Receptors, KIR; D055630:Receptors, NK Cell Lectin-Like; D055607:Receptors, Natural Killer Cell