Interaction of the NK cell inhibitory receptor Ly49A with H-2Dd: identification of a site distinct from the TCR site.
Natural killer cell function is controlled by interaction of NK receptors with MHC I molecules expressed on target cells. We describe the binding of bacterially expressed Ly49A, the prototype murine NK inhibitory receptor, to similarly engineered H-2Dd. Despite its homology to C-type lectins, Ly49A binds independently of carbohydrate and Ca2+ and shows specificity for MHC I but not bound peptide. The affinity of the Ly49A/H-2Dd interaction as determined by surface plasmon resonance is from 6 to 26 microM at 25 degrees C and is greater by ultracentrifugation at 4 degrees C. Biotinylated Ly49A stains H-2Dd-expressing cells. Competition experiments indicate that the Ly49A and T cell receptor (TCR) binding sites on MHC I are distinct, suggesting complex regulation of cells that bear both TCR and NK cell receptors.
Natarajan
K
K
Molecular Biology Section, Laboratory of Immunology, National Institutes of Health, Bethesda, Maryland 20892, USA.
Boyd
L F
LF
Schuck
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P
Yokoyama
W M
WM
Eliat
D
D
Margulies
D H
DH
D000818:Animals; D000950:Antigens, Ly; D001665:Binding Sites; D001667:Binding, Competitive; D019921:Biotinylation; D002118:Calcium / Q000378:metabolism; D006031:Glycosylation; D006183:H-2 Antigens / Q000378:metabolism*; D064532:Histocompatibility Antigen H-2D; D007694:Killer Cells, Natural / Q000276:immunology*; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008958:Models, Molecular; D055650:NK Cell Lectin-Like Receptor Subfamily A; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D017510:Protein Folding; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D055630:Receptors, NK Cell Lectin-Like; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020349:Surface Plasmon Resonance; D014461:Ultracentrifugation
D000950:Antigens, Ly; D006183:H-2 Antigens; D064532:Histocompatibility Antigen H-2D; C527088:Klra1 protein, mouse; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D055650:NK Cell Lectin-Like Receptor Subfamily A; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; D055630:Receptors, NK Cell Lectin-Like; D011993:Recombinant Fusion Proteins; D002118:Calcium