title: KIR3DS1-Specific D0 Domain Polymorphisms Disrupt KIR3DL1 Surface Expression and HLA Binding.
abstract: KIR3DL1 is a polymorphic inhibitory receptor that modulates NK cell activity through interacting with HLA-A and HLA-B alleles that carry the Bw4 epitope. Amino acid polymorphisms throughout KIR3DL1 impact receptor surface expression and affinity for HLA. KIR3DL1/S1 encodes inhibitory and activating alleles, but despite high homology with KIR3DL1, the activating receptor KIR3DS1 does not bind the same ligand. Allele KIR3DL1*009 resulted from a gene recombination event between the inhibitory receptor allele KIR3DL1*001 and the activating receptor allele KIR3DS1*013. This study analyzed the functional impact of KIR3DS1-specific polymorphisms on KIR3DL1*009 surface expression, binding to HLA, and functional capacity. Flow-cytometric analysis of primary human NK cells as well as transfected HEK293T cells shows that KIR3DL1*009 is expressed at a significantly lower surface density compared with KIR3DL1*001. Using recombinant proteins of KIR3DL1*001, KIR3DL1*009, and KIR3DS1*013 to analyze binding to HLA, we found that although KIR3DL1*009 displayed some evidence of binding to HLA compared with KIR3DS1*013, the binding was minimal compared with KIR3DL1*001 and KIR3DL1*005. Mutagenesis of polymorphic sites revealed that the surface phenotype and reduced binding of KIR3DL1*009 are caused by the combined amino acid polymorphisms at positions 58 and 92 within the D0 extracellular domain. Resulting from these effects, KIR3DL1*009(+) NK cells exhibited significantly less inhibition by HLA-Bw4(+) target cells compared with KIR3DL1*001(+) NK cells. The data from this study contribute novel insight into how KIR3DS1-specific polymorphisms in the extracellular region impact KIR3DL1 surface expression, ligand binding, and inhibitory function.
authors.affiliation: Immunology Program, Sloan Kettering Institute, New York, NY 10065;
authors.forename: Tiernan J
authors.initials: TJ
authors.lastname: Mulrooney
authors.affiliation: Immunology Program, Sloan Kettering Institute, New York, NY 10065;
authors.forename: Aaron C
authors.initials: AC
authors.lastname: Zhang
authors.affiliation: Department of Structural Biology, Sloan Kettering Institute, New York, NY 10065;
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Goldgur
authors.affiliation: Immunology Program, Sloan Kettering Institute, New York, NY 10065;
authors.forename: Jeanette E
authors.initials: JE
authors.lastname: Boudreau
authors.affiliation: Immunology Program, Sloan Kettering Institute, New York, NY 10065; Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065; and Weill Cornell Medical College, Cornell University, New York, NY 10065 hsuk@mskcc.org.
authors.forename: Katharine C
authors.initials: KC
authors.lastname: Hsu
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D057809:HEK293 Cells; D015234:HLA-A Antigens / Q000235:genetics / Q000276:immunology*; D015235:HLA-B Antigens / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D054341:Receptors, KIR3DL1 / Q000096:biosynthesis / Q000235:genetics*; D054349:Receptors, KIR3DS1 / Q000235:genetics*
chemical_list: D015234:HLA-A Antigens; D015235:HLA-B Antigens; C515083:KIR3DL1 protein, human; D054341:Receptors, KIR3DL1; D054349:Receptors, KIR3DS1