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Updated: May 22, 2026
Peptide Scanning-assisted Identification of a Monoclonal Antibody-recognized Linear B-cell Epitope
Published on: March 24, 2017
Dimerization of NKp46 receptor is essential for NKp46-mediated lysis: characterization of the dimerization site by
Michal Jaron-Mendelson1, Rami Yossef, Michael Y Appel
1The Shraga Segal Department of Microbiology and Immunology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel.
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.
Insights
Natural killer cell receptor NKp46 is crucial for target cell lysis. A specific epitope, pep4, was identified, inhibiting lysis by blocking NKp46 dimerization, a key step in NK cell activation.
Area of Science:
- Immunology
- Cellular Biology
- Molecular Biology
Background:
- NKp46 is a primary activating receptor on natural killer (NK) cells.
- NKp46 mediates target cell lysis and its membrane-proximal domain (NKp46D2) retains ligand binding and lytic functions.
Purpose of the Study:
- To investigate the functional role of the NKp46D2 domain.
- To identify specific epitopes within NKp46D2 involved in NK cell-mediated lysis.
- To elucidate the mechanism of NKp46-mediated cytotoxicity.
Main Methods:
- Peptide-based epitope mapping to identify functional regions of NKp46D2.
- Molecular modeling and mutagenesis to analyze epitope function.
- Fluorescent resonance energy transfer (FRET) analysis to study protein-protein interactions at the cellular level.
Main Results:
- A linear epitope, pep4 (amino acids 136-155), was identified within NKp46D2 that inhibits NKp46-mediated lysis.
- Pep4 interacts with NKp46 and its presence blocks NK cell-mediated lysis.
- Modeling and mutagenesis revealed pep4's role in NKp46 homodimerization, with residues R145 and D147 being critical.
- R145Q mutation reduced NKp46 binding to target cells.
- FRET analysis confirmed pep4's involvement in the dimerization of cell membrane-associated NKp46.
Conclusions:
- The NKp46-derived pep4 site is part of the NKp46 homodimerization surface.
- NKp46 homodimerization is a critical mechanism contributing to NK cell-mediated lysis.
- Targeting the pep4 epitope offers a potential strategy to modulate NK cell cytotoxicity.
