Dynamic redistribution of the activating 2B4/SAP complex at the cytotoxic NK cell immune synapse.
The 2B4 molecule (CD244) has been described as a coreceptor in human NK cell activation. However, the behavior of 2B4 during the cytotoxic NK cell immune synapse (NK-IS) formation remains undetermined. In this study, we demonstrate the redistribution of 2B4 and the signaling adaptor molecule, signaling lymphocyte activation molecule-associated protein (SAP), to the cytotoxic NK-IS upon formation of conjugates between resting NK cells and EBV-infected 721.221 human cells. Confocal microscopy showed that 2B4 localized at the central supramolecular activation cluster, surrounded by a peripheral supramolecular activation cluster containing talin within NK cell and ICAM-1 on target cells. Videomicroscopy studies with 2B4-GFP-transfected NK cells revealed that 2B4 redistributed to cytotoxic NK-IS as soon as the cell contact occurred. Simultaneously, a SAP-GFP also clustered at the contact site, where it remained during the interaction period. The 2B4 molecular clusters remained bound to the target cell even after NK cell detachment. These results underscore the function of 2B4 as an adhesion molecule and suggest a relevant role in the initial binding, scanning of target cells, and formation of cytotoxic NK-IS. Finally, these findings are indicative of an important role of the activating 2B4/signaling lymphocyte activation molecule-associated protein complex during the recognition of EBV-infected cells.
Roda-Navarro
Pedro
P
Unidad de Biología Molecular, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Spain.
Mittelbrunn
María
M
Ortega
Mara
M
Howie
Duncan
D
Terhorst
Cox
C
Sánchez-Madrid
Francisco
F
Fernández-Ruiz
Elena
E
D015703:Antigens, CD / Q000097:blood / Q000378:metabolism* / Q000502:physiology; D002352:Carrier Proteins / Q000097:blood / Q000378:metabolism* / Q000502:physiology; D002450:Cell Communication / Q000276:immunology*; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral / Q000276:immunology; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic; D004854:Herpesvirus 4, Human / Q000276:immunology; D006801:Humans; D007399:Interphase / Q000276:immunology; D047908:Intracellular Signaling Peptides and Proteins; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000097:blood / Q000378:metabolism* / Q000502:physiology; D011971:Receptors, Immunologic / Q000097:blood / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction / Q000276:immunology; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D000071176:Signaling Lymphocytic Activation Molecule Family; D013347:Subcellular Fractions / Q000276:immunology / Q000378:metabolism; D018909:src Homology Domains / Q000276:immunology
D015703:Antigens, CD; C084093:CD244 protein, human; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; C114953:SH2D1A protein, human; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D000071176:Signaling Lymphocytic Activation Molecule Family