The adaptor protein shc is involved in the negative regulation of NK cell-mediated cytotoxicity.
The activation of protein tyrosine kinase(s) (PTK) is a critical event required for the development of NK cell-mediated cytotoxicity. Here we demonstrate that the adaptor protein shc undergoes tyrosine phosphorylation during the generation of antibody-dependent cellular cytotoxicity (ADCC) and natural killing. In addition, we report that, upon direct or antibody-dependent target cell interaction, shc coprecipitates with the Src homology 2 (SH2)-containing inositol phosphatase, SHIP. To gain information on the functional role of shc in NK cytotoxicity, we overexpressed wild-type or dominant negative shc constructs in the human NKL cell line. Our findings show a consistent shc-mediated down-regulation of ADCC and natural killing. Such functional effect correlates with a perturbation of the phosphoinositide (PI) metabolism by means of a shc-mediated negative regulation of inositol 1,4,5 triphosphate (IP3) generation and intracellular calcium flux upon CD16 ligation. Furthermore, our data show that dominant-negative shc-mediated perturbation of shc/SHIP interaction leads to inhibition of ligand-dependent SHIP recruitment to CD16 zeta chain. We suggest that shc plays a role of negative adaptor by modulating SHIP recruitment to activation receptors involved in the generation of NK cytotoxic function.
Galandrini
R
R
Department of Experimental Medicine and Pathology, Istituto Pasteur-Fondazione Cenci Bolognetti, University "La Sapienza", Rome, Italy. Ricciarda.Galandrini@uniroma1.it
Tassi
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Morrone
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S
Lanfrancone
L
L
Pelicci
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P
Piccoli
M
M
Frati
L
L
Santoni
A
A
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000920:Antibody-Dependent Cell Cytotoxicity; D020013:Calcium Signaling; D002460:Cell Line; D002478:Cells, Cultured; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic; D006801:Humans; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000276:immunology*; D046911:Macromolecular Substances; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010744:Phosphoric Monoester Hydrolases; D019000:Phosphotyrosine / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D017452:Receptors, IgG / Q000276:immunology; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014162:Transfection; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D046911:Macromolecular Substances; D011506:Proteins; D017452:Receptors, IgG; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D019000:Phosphotyrosine; D010744:Phosphoric Monoester Hydrolases; C098706:INPPL1 protein, human; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases