title: The adaptor 3BP2 activates CD244-mediated cytotoxicity in PKC- and SAP-dependent mechanisms.
abstract: Natural killer (NK) cell cytotoxicity requires triggering of activation receptors over inhibitory receptors. CD244, a member of CD150 receptor family, positively regulates NK-mediated lyses by activating an intracellular multiproteic signaling network that involves the adaptors X-linked lymphoproliferative gene product SAP and 3BP2. However, the exact mechanisms used by 3BP2 to enhance CD244-mediated cytotoxicity are still not fully understood. Here using the human NK cell line YT-overexpressing 3BP2, we found that the adaptor increases CD244, PI3K, and Vav phosphorylation upon CD244 engagement. The use of enzymatic inhibitors revealed that 3BP2-dependent cytolysis enhancement was PKC-dependent and PI3K-ERK independent. Furthermore, 3BP2 overexpression enhanced PKC delta phosphorylation. SAP knockdown expression inhibited PKC delta activation, indicating that the activating role played by 3BP2 depends upon the presence of SAP. In conclusion, our data show that 3BP2 acts downstream of SAP, increases CD244 phosphorylation and links the receptor with PI3K, Vav, PLC gamma, and PKC downstream events in order to achieve maximum NK killing function.
authors.affiliation: Immunoreceptors group, Institut d'Investigació August Pi i Sunyer (IDIBAPS), Immunology Unit, Department of Cellular Biology and Pathology, Medical School, University of Barcelona, Barcelona, Spain.
authors.forename: Ifigenia
authors.initials: I
authors.lastname: Saborit-Villarroya
authors.forename: Agueda
authors.initials: A
authors.lastname: Martinez-Barriocanal
authors.forename: Irene
authors.initials: I
authors.lastname: Oliver-Vila
authors.forename: Pablo
authors.initials: P
authors.lastname: Engel
authors.forename: Joan
authors.initials: J
authors.lastname: Sayos
authors.forename: Margarita
authors.initials: M
authors.lastname: Martin
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism*; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D002460:Cell Line; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D051379:Mice; D018448:Models, Immunological; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051966:Phospholipase C gamma / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D051745:Protein Kinase C-delta / Q000378:metabolism*; D051567:Proto-Oncogene Proteins c-vav / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D000071176:Signaling Lymphocytic Activation Molecule Family; D000077191:Wortmannin
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000730:Androstadienes; D015703:Antigens, CD; C084093:CD244 protein, human; D047908:Intracellular Signaling Peptides and Proteins; D051567:Proto-Oncogene Proteins c-vav; D011971:Receptors, Immunologic; C114953:SH2D1A protein, human; C109073:SH3BP2 protein, human; D000071179:Signaling Lymphocytic Activation Molecule Associated Protein; D000071176:Signaling Lymphocytic Activation Molecule Family; C496618:VAV1 protein, human; D019000:Phosphotyrosine; D019869:Phosphatidylinositol 3-Kinases; D051745:Protein Kinase C-delta; D048049:Extracellular Signal-Regulated MAP Kinases; D051966:Phospholipase C gamma; D000077191:Wortmannin