title: The adaptor protein 3BP2 binds human CD244 and links this receptor to Vav signaling, ERK activation, and NK cell killing.
abstract: Adaptor proteins, molecules that mediate intermolecular interactions, are crucial for cellular activation. The adaptor 3BP2 has been shown to positively regulate NK cell-mediated cytotoxicity. In this study we present evidence for a physical interaction between 3BP2 and the CD244 receptor. CD244, a member of the CD150 family, is a cell surface protein expressed on NK, CD8+ T, and myeloid cells. CD244 interacts via its Src homology 2 domain with the X-linked lymphoproliferative disease gene product signaling lymphocytic activation molecule-associated protein (SAP)/SH2 domain protein 1A. 3BP2 interacts with human but not murine CD244. CD244-3BP2 interaction was direct and regulated by phosphorylation, as shown by a three-hybrid analysis in yeast and NK cells. Tyr337 on CD244, part of a consensus motif for SAP/SH2 domain protein 1A binding, was critical for the 3BP2 interaction. Although mutation of Tyr337 to phenylalanine abrogated human 3BP2 binding, we still observed SAP association, indicating that this motif is not essential for SAP recruitment. CD244 ligation induced 3BP2 phosphorylation and Vav-1 recruitment. Overexpression of 3BP2 led to an increase in the magnitude and duration of ERK activation, after CD244 triggering. This enhancement was concomitant with an increase in cytotoxicity due to CD244 ligation. However, no differences in IFN-gamma secretion were found when normal and 3BP2-transfected cells were compared. These results indicate that CD244-3BP2 association regulates cytolytic function but not IFN-gamma release, reinforcing the hypothesis that, in humans, CD244-mediated cytotoxicity and IFN-gamma release involve distinct NK pathways.
authors.affiliation: Unitat d'Immunología, Departament de Biologia Cellular i Anatomia Patològica, Facultat de Medicina, Universitat de Barcelona, Spain.
authors.forename: Ifigènia
authors.initials: I
authors.lastname: Saborit-Villarroya
authors.forename: Juana M
authors.initials: JM
authors.lastname: Del Valle
authors.forename: Xavier
authors.initials: X
authors.lastname: Romero
authors.forename: Enric
authors.initials: E
authors.lastname: Esplugues
authors.forename: Pilar
authors.initials: P
authors.lastname: Lauzurica
authors.forename: Pablo
authors.initials: P
authors.lastname: Engel
authors.forename: Margarita
authors.initials: M
authors.lastname: Martín
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism* / Q000502:physiology; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D003602:Cytotoxicity, Immunologic; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007694:Killer Cells, Natural / Q000502:physiology*; D008024:Ligands; D008562:Membrane Glycoproteins / Q000378:metabolism* / Q000502:physiology; D051379:Mice; D010766:Phosphorylation; D011971:Receptors, Immunologic / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D000071176:Signaling Lymphocytic Activation Molecule Family; D015003:Yeasts / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; C084093:CD244 protein, human; D008024:Ligands; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; C484644:Sh3bp2 protein, mouse; D000071176:Signaling Lymphocytic Activation Molecule Family; D007371:Interferon-gamma; D048049:Extracellular Signal-Regulated MAP Kinases