Ubiquitin-dependent endocytosis of NKG2D-DAP10 receptor complexes activates signaling and functions in human NK cells.
Cytotoxic lymphocytes share the presence of the activating receptor NK receptor group 2, member D (NKG2D) and the signaling-competent adaptor DNAX-activating protein 10 (DAP10), which together play an important role in antitumor immune surveillance. Ligand stimulation induces the internalization of NKG2D-DAP10 complexes and their delivery to lysosomes for degradation. In experiments with human NK cells and cell lines, we found that the ligand-induced endocytosis of NKG2D-DAP10 depended on the ubiquitylation of DAP10, which was also required for degradation of the internalized complexes. Moreover, through combined biochemical and microscopic analyses, we showed that ubiquitin-dependent receptor endocytosis was required for the activation of extracellular signal-regulated kinase (ERK) and NK cell functions, such as the secretion of cytotoxic granules and the inflammatory cytokine interferon-γ. These results suggest that NKG2D-DAP10 endocytosis represents a means to decrease cell surface receptor abundance, as well as to control signaling outcome in cytotoxic lymphocytes.
Department of Molecular Medicine, "Sapienza" University of Rome, 00161 Rome, Italy.
Linda
L
Quatrini
Department of Molecular Medicine, "Sapienza" University of Rome, 00161 Rome, Italy.
Rosa
R
Molfetta
Department of Molecular Medicine, "Sapienza" University of Rome, 00161 Rome, Italy.
Beatrice
B
Zitti
Istituto Italiano di Tecnologia, CLNS@Sapienza, "Sapienza" University of Rome, 00161 Rome, Italy.
Giovanna
G
Peruzzi
Department of Molecular Medicine, "Sapienza" University of Rome, 00161 Rome, Italy.
Cinzia
C
Fionda
Department of Experimental Medicine, "Sapienza" University of Rome, 00161 Rome, Italy.
Cristina
C
Capuano
Department of Experimental Medicine, "Sapienza" University of Rome, 00161 Rome, Italy.
Ricciarda
R
Galandrini
Department of Molecular Medicine, "Sapienza" University of Rome, 00161 Rome, Italy.
Marco
M
Cippitelli
Department of Molecular Medicine, "Sapienza" University of Rome, 00161 Rome, Italy. Istituto Pasteur-Fondazione Cenci Bolognetti, "Sapienza" University of Rome, 00161 Rome, Italy. rossella.paolini@uniroma1.it angela.santoni@uniroma1.it.
Angela
A
Santoni
Department of Molecular Medicine, "Sapienza" University of Rome, 00161 Rome, Italy. Istituto Pasteur-Fondazione Cenci Bolognetti, "Sapienza" University of Rome, 00161 Rome, Italy. rossella.paolini@uniroma1.it angela.santoni@uniroma1.it.
Rossella
R
Paolini
D002460:Cell Line; D004705:Endocytosis / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology*; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000235:genetics / Q000276:immunology*; D059748:Proteolysis; D011971:Receptors, Immunologic / Q000235:genetics / Q000276:immunology*; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D025801:Ubiquitin / Q000235:genetics / Q000276:immunology*
C120528:HCST protein, human; C527085:KLRK1 protein, human; D055655:NK Cell Lectin-Like Receptor Subfamily K; D011971:Receptors, Immunologic; D025801:Ubiquitin