Phosphatidylinositol 3-kinase activation is required to form the NKG2D immunological synapse.
The receptor NKG2D allows natural killer (NK) cells to detect virally infected, stressed, and tumor cells. In human cells, NKG2D signaling is mediated through the associated DAP10 adapter. Here we show that engagement of NKG2D by itself is sufficient to stimulate the formation of the NK immunological synapse (NKIS), with recruitment of NKG2D to the center synapse. Mutagenesis studies of DAP10 revealed that the phosphatidylinositol 3-kinase binding site, but not the Grb2 binding site, was required and sufficient for recruitment of DAP10 to the NKIS. Surprisingly, we found that in the absence of the Grb2 binding site, Grb2 was still recruited to the NKIS. Since the recruitment of Grb2 was dependent on phosphatidylinositol-(3,4,5)-trisphosphate (PIP3), we explored the possibility that recruitment to the NKIS is mediated by a pleckstrin homology (PH) domain-containing binding partner for Grb2. We found that the PH domain of SOS1, but not that of Vav1, was able to be recruited by PIP3. These results provide new insights into the mechanism of immunological synapse formation and also demonstrate how multiple mechanisms can be used to recruit the same signaling proteins to the plasma membrane.
Giurisato
Emanuele
E
Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA.
Cella
Marina
M
Takai
Toshiyuki
T
Kurosaki
Tomohiro
T
Feng
Yungfeng
Y
Longmore
Gregory D
GD
Colonna
Marco
M
Shaw
Andrey S
AS
D000199:Actins / Q000378:metabolism; D020816:Amino Acid Motifs; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D003594:Cytoplasmic Granules / Q000378:metabolism; D003602:Cytotoxicity, Immunologic; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D051380:GRB2 Adaptor Protein / Q000378:metabolism; D006801:Humans; D007694:Killer Cells, Natural / Q000378:metabolism; D051379:Mice; D055655:NK Cell Lectin-Like Receptor Subfamily K; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000096:biosynthesis; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D051567:Proto-Oncogene Proteins c-vav / Q000737:chemistry / Q000378:metabolism; D011971:Receptors, Immunologic / Q000737:chemistry / Q000378:metabolism*; D055607:Receptors, Natural Killer Cell; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D020837:SOS1 Protein / Q000378:metabolism
D000199:Actins; D000596:Amino Acids; D048049:Extracellular Signal-Regulated MAP Kinases; D051380:GRB2 Adaptor Protein; D055655:NK Cell Lectin-Like Receptor Subfamily K; D019869:Phosphatidylinositol 3-Kinases; D018129:Phosphatidylinositol Phosphates; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051567:Proto-Oncogene Proteins c-vav; D011971:Receptors, Immunologic; D055607:Receptors, Natural Killer Cell; D011993:Recombinant Fusion Proteins; D020837:SOS1 Protein; C527085:KLRK1 protein, human; C527086:Klrk1 protein, mouse; C060974:phosphatidylinositol 3,4,5-triphosphate