title: Dimerization of NKp46 receptor is essential for NKp46-mediated lysis: characterization of the dimerization site by epitope mapping.
abstract: NKp46 is a primary activating receptor of NK cells that is involved in lysis of target cells by NK cells. Previous studies showed that the membrane-proximal domain of NKp46 (NKp46D2) retained the binding of NKp46 to its ligands and is involved in lysis. We studied NKp46D2 by using a peptide-based epitope mapping approach and identified an NKp46D2-derived linear epitope that inhibited NKp46-mediated lysis. The epitope, designated as pep4 (aa 136-155), interacted with NKp46, and lysis by NK cells was inhibited by the presence of pep4. Through modeling and mutagenesis, we showed that pep4 could be involved in NKp46 homodimerization. R145 and D147 contribute to the function of pep4, and R145Q mutation in recombinant NKp46 reduced its binding to target cells. At the cellular level, fluorescent resonance energy transfer analysis revealed that pep4 is indeed involved in dimerization of cell membrane-associated NKp46. We suggest that the NKp46-derived pep4 site is part of the dimerization surface of NKp46 and that NKp46 dimerization contributes to NKp46-mediated lysis by NK cells.
authors.affiliation: The Shraga Segal Department of Microbiology and Immunology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
authors.forename: Michal
authors.initials: M
authors.lastname: Jaron-Mendelson
authors.forename: Rami
authors.initials: R
authors.lastname: Yossef
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Appel
authors.forename: Alon
authors.initials: A
authors.lastname: Zilka
authors.forename: Uzi
authors.initials: U
authors.lastname: Hadad
authors.forename: Fabian
authors.initials: F
authors.lastname: Afergan
authors.forename: Benyamin
authors.initials: B
authors.lastname: Rosental
authors.forename: Stanislav
authors.initials: S
authors.lastname: Engel
authors.forename: Shlomo
authors.initials: S
authors.lastname: Nedvetzki
authors.forename: Alex
authors.initials: A
authors.lastname: Braiman
authors.forename: Angel
authors.initials: A
authors.lastname: Porgador
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D018604:Epitope Mapping; D005434:Flow Cytometry; D006801:Humans; D007694:Killer Cells, Natural / Q000737:chemistry* / Q000276:immunology* / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000276:immunology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D055627:Natural Cytotoxicity Triggering Receptor 1 / Q000737:chemistry* / Q000276:immunology* / Q000378:metabolism*; D010455:Peptides; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D020349:Surface Plasmon Resonance; D014162:Transfection
chemical_list: D055627:Natural Cytotoxicity Triggering Receptor 1; D010455:Peptides