title: Dephosphorylation of the adaptor LAT and phospholipase C-γ by SHP-1 inhibits natural killer cell cytotoxicity.
abstract: Natural killer (NK) cells discriminate between healthy cells and virally infected or transformed self-cells by tuning activating and inhibitory signals received through cell surface receptors. Inhibitory receptors inhibit NK cell function by recruiting and activating the tyrosine phosphatase Src homology 2 (SH2) domain-containing protein tyrosine phosphatase-1 (SHP-1) to the plasma membrane. However, to date, the guanine nucleotide exchange factor VAV1 is the only direct SHP-1 substrate identified in NK cells. We reveal that the adaptor protein linker for activation of T cells (LAT) as well as phospholipase C-γ1 (PLC-γ1) and PLC-γ2 are SHP-1 substrates. Dephosphorylation of Tyr(132) in LAT by SHP-1 in NK cells abrogated the recruitment of PLC-γ1 and PLC-γ2 to the immunological synapse between the NK cell and a cancer cell target, which reduced NK cell degranulation and target cell killing. Furthermore, the ubiquitylation of LAT by the E3 ubiquitin ligases c-Cbl and Cbl-b, which was induced by LAT phosphorylation, led to the degradation of LAT in response to the engagement of inhibitory receptors on NK cells, which abrogated NK cell cytotoxicity. Knockdown of the Cbl proteins blocked LAT ubiquitylation, which promoted NK cell function. Expression of a ubiquitylation-resistant mutant LAT blocked inhibitory receptor signaling, enabling cells to become activated. Together, these data identify previously uncharacterized SHP-1 substrates and inhibitory mechanisms that determine the response of NK cells.
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Omri
authors.initials: O
authors.lastname: Matalon
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Sophia
authors.initials: S
authors.lastname: Fried
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Aviad
authors.initials: A
authors.lastname: Ben-Shmuel
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Maor H
authors.initials: MH
authors.lastname: Pauker
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Noah
authors.initials: N
authors.lastname: Joseph
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Danielle
authors.initials: D
authors.lastname: Keizer
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
authors.forename: Marina
authors.initials: M
authors.lastname: Piterburg
authors.affiliation: The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel. mira.barda-saad@biu.ac.il.
authors.forename: Mira
authors.initials: M
authors.lastname: Barda-Saad
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D005434:Flow Cytometry; D031541:Fluorescence Resonance Energy Transfer; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007694:Killer Cells, Natural / Q000166:cytology* / Q000378:metabolism; D008213:Lymphocyte Activation; D008565:Membrane Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D016296:Mutagenesis; D009154:Mutation; D051966:Phospholipase C gamma / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000378:metabolism*; D034622:RNA Interference; D054342:Receptors, KIR2DL1 / Q000378:metabolism; D014162:Transfection; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C093100:KIR2DL1 protein, human; C110810:LAT protein, human; D008565:Membrane Proteins; D054342:Receptors, KIR2DL1; D025801:Ubiquitin; D004247:DNA; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; C522157:PLCG1 protein, human; D051966:Phospholipase C gamma; D002118:Calcium