scholarly journals The murine cytomegalovirus immunoevasin gp40/m152 inhibits NKG2D receptor RAE-1γ by intracellular retention and cell surface masking

2021 ◽  
Vol 134 (11) ◽  
Author(s):  
Natalia Lis ◽  
Zeynep Hein ◽  
Swapnil S. Ghanwat ◽  
Venkat R. Ramnarayan ◽  
Benedict J. Chambers ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cell Activation ◽  
Secretory Pathway ◽  
Nk Cell ◽  
Retention Mechanism ◽  
Host Protein ◽  
Murine Cytomegalovirus ◽  
Early Secretory Pathway ◽  
P24 Protein ◽  
Nkg2d Receptor

ABSTRACT NKG2D (also known as KLRK1) is a crucial natural killer (NK) cell-activating receptor, and the murine cytomegalovirus (MCMV) employs multiple immunoevasins to avoid NKG2D-mediated activation. One of the MCMV immunoevasins, gp40 (m152), downregulates the cell surface NKG2D ligand RAE-1γ (also known as Raet1c) thus limiting NK cell activation. This study establishes the molecular mechanism by which gp40 retains RAE-1γ in the secretory pathway. Using flow cytometry and pulse-chase analysis, we demonstrate that gp40 retains RAE-1γ in the early secretory pathway, and that this effect depends on the binding of gp40 to a host protein, TMED10, a member of the p24 protein family. We also show that the TMED10-based retention mechanism can be saturated, and that gp40 has a backup mechanism as it masks RAE-1γ on the cell surface, blocking the interaction with the NKG2D receptor and thus NK cell activation.

scholarly journals The MCMV immunoevasin gp40/m152 inhibits NKG2D receptor RAE-1γ by intracellular retention and cell surface masking

2020 ◽  
Author(s):  
Natalia Lis ◽  
Zeynep Hein ◽  
Swapnil S. Ghanwat ◽  
Venkat Raman Ramnarayan ◽  
Benedict J. Chambers ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cell Activation ◽  
Secretory Pathway ◽  
Nk Cell ◽  
Retention Mechanism ◽  
Host Protein ◽  
Murine Cytomegalovirus ◽  
Early Secretory Pathway ◽  
P24 Protein ◽  
Nkg2d Receptor

AbstractNKG2D is a crucial Natural Killer (NK) cell activating receptor, and the murine cytomegalovirus (MCMV) employs multiple immunoevasins in order to avoid NKG2D-mediated activation. One of the MCMV immunoevasins, gp40 (m152), downregulates the cell surface NKG2D ligand, RAE-1γ, thus limiting NK cell activation. This study establishes the molecular mechanism by which gp40 retains RAE-1γ in the secretory pathway. Using flow cytometry and pulse chase analysis, we demonstrate that gp40 retains RAE-1γ in the early secretory pathway, and that this effect depends on the binding of gp40 to a host protein, TMED10, a member of the p24 protein family. We also show that the TMED10-based retention mechanism can be saturated, and that gp40 has a backup mechanism as it masks RAE-1γ on the cell surface, blocking the interaction with the NKG2D receptor and thus NK cell activation.Summary statementMCMV immunoevasin gp40 inhibits the NKG2D-activating ligand RAE-1γ by intracellular retention that depends on the p24 member TMED10, and additionally by masking it at the cell surface.

scholarly journals Regulation of the Expression, Oligomerisation and Signaling of the Inhibitory Receptor CLEC12A by Cysteine Residues in the Stalk Region

2021 ◽  
Vol 22 (19) ◽  
pp. 10207
Author(s):  
Julien Vitry ◽  
Guillaume Paré ◽  
Andréa Murru ◽  
Xavier Charest-Morin ◽  
Halim Maaroufi ◽  
...  
Keyword(s):  
Cell Surface ◽  
Cell Activation ◽  
Secretory Pathway ◽  
Surface Expression ◽  
Site Directed Mutagenesis ◽  
Cell Surface Expression ◽  
Dependent Manner ◽  
Inhibitory Receptor ◽  
Lectin Receptors ◽  
Stalk Domain

CLEC12A is a myeloid inhibitory receptor that negatively regulates inflammation in mouse models of autoimmune and autoinflammatory arthritis. Reduced CLEC12A expression enhances myeloid cell activation and inflammation in CLEC12A knock-out mice with collagen antibody-induced or gout-like arthritis. Similarly to other C-type lectin receptors, CLEC12A harbours a stalk domain between its ligand binding and transmembrane domains. While it is presumed that the cysteines in the stalk domain have multimerisation properties, their role in CLEC12A expression and/or signaling remain unknown. We thus used site-directed mutagenesis to determine whether the stalk domain cysteines play a role in CLEC12A expression, internalisation, oligomerisation, and/or signaling. Mutation of C118 blocks CLEC12A transport through the secretory pathway diminishing its cell-surface expression. In contrast, mutating C130 does not affect CLEC12A cell-surface expression but increases its oligomerisation, inducing ligand-independent phosphorylation of the receptor. Moreover, we provide evidence that CLEC12A dimerisation is regulated in a redox-dependent manner. We also show that antibody-induced CLEC12A cross-linking induces flotillin oligomerisation in insoluble membrane domains in which CLEC12A signals. Taken together, these data indicate that the stalk cysteines in CLEC12A differentially modulate this inhibitory receptor’s expression, oligomerisation and signaling, suggestive of the regulation of CLEC12A in a redox-dependent manner during inflammation.

scholarly journals PVRIG is a novel NK cell immune checkpoint receptor in acute myeloid leukemia

Haematologica ◽  
2020 ◽  
pp. 0-0
Author(s):  
Jessica Li ◽  
Sarah Whelan ◽  
Maya F. Kotturi ◽  
Deborah Meyran ◽  
Criselle D’Souza ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Cell Surface ◽  
Nk Cells ◽  
Immune Checkpoint ◽  
Myeloid Leukemia ◽  
Cell Activation ◽  
Nk Cell ◽  
Blocking Antibody ◽  
Poliovirus Receptor ◽  
Acute Myeloid

This study explored the novel immune checkpoint poliovirus receptor-related immunoglobulin domain-containing (PVRIG) in acute myeloid leukemia (AML). We showed that AML patient blasts consistently expressed the PVRIG ligand (poliovirus receptor-related 2, PVRL2). Furthermore, PVRIG blockade significantly enhanced NK cell killing of PVRL2+, poliovirus receptor (PVR)lo AML cell lines, and significantly increased NK cell activation and degranulation in the context of patient primary AML blasts. However, in AML patient bone marrow, NK cell PVRIG expression levels were not increased. To understand how PVRIG blockade might potentially be exploited therapeutically, we investigated the biology of PVRIG and revealed that NK cell activation resulted in reduced PVRIG expression on the cell surface. This occurred whether NK cells were activated by tumour cell recognition, cytokines (IL-2 and IL-12) or activating receptor stimulation (CD16 and NKp46). PVRIG was present at higher levels in the cytoplasm than on the cell surface, particularly on CD56bright NK cells, which further increased cytoplasmic PVRIG levels following IL-2 and IL-12 activation. PVRIG was continually transported to the cell surface via the endoplasmic reticulum (ER) and Golgi in both unstimulated and activated NK cells. Taken together, our findings suggest that anti- PVRIG blocking antibody functions by binding to surface-bound PVRIG, which undergoes rapid turnover in both unstimulated and activated NK cells. We conclude that the PVRIGPVRL2 immune checkpoint axis can feasibly be targeted with PVRIG blocking antibody for NK-mediated immunotherapy of PVRL2+ AML.

scholarly journals HIV-1 Vpr up-regulates expression of ligands for the activating NKG2D receptor and promotes NK cell–mediated killing

Blood ◽  
2010 ◽  
Vol 115 (7) ◽  
pp. 1354-1363 ◽  
Author(s):  
Jonathan Richard ◽  
Sardar Sindhu ◽  
Tram N. Q. Pham ◽  
Jean-Philippe Belzile ◽  
Éric A. Cohen
Keyword(s):  
Dna Damage ◽  
Cell Surface ◽  
Nk Cell ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Target Cells ◽  
Nkg2d Ligands ◽  
Infected Cells ◽  
Nkg2d Receptor ◽  
Hiv 1

AbstractHIV up-regulates cell-surface expression of specific ligands for the activating NKG2D receptor, including ULBP-1, -2, and -3, but not MICA or MICB, in infected cells both in vitro and in vivo. However, the viral factor(s) involved in NKG2D ligand expression still remains undefined. HIV-1 Vpr activates the DNA damage/stress-sensing ATR kinase and promotes G2 cell-cycle arrest, conditions known to up-regulate NKG2D ligands. We report here that HIV-1 selectively induces cell-surface expression of ULBP-2 in primary CD4+ T lymphocytes by a process that is Vpr dependent. Importantly, Vpr enhanced the susceptibility of HIV-1–infected cells to NK cell–mediated killing. Strikingly, Vpr alone was sufficient to up-regulate expression of all NKG2D ligands and thus promoted efficient NKG2D-dependent NK cell–mediated killing. Delivery of virion-associated Vpr via defective HIV-1 particles induced analogous biologic effects in noninfected target cells, suggesting that Vpr may act similarly beyond infected cells. All these activities relied on Vpr ability to activate the ATR-mediated DNA damage/stress checkpoint. Overall, these results indicate that Vpr is a key determinant responsible for HIV-1–induced up-regulation of NKG2D ligands and further suggest an immunomodulatory role for Vpr that may not only contribute to HIV-1–induced CD4+ T-lymphocyte depletion but may also take part in HIV-1–induced NK-cell dysfunction.

scholarly journals Continuous engagement of a self-specific activation receptor induces NK cell tolerance

2008 ◽  
Vol 205 (8) ◽  
pp. 1829-1841 ◽  
Author(s):  
Sandeep K. Tripathy ◽  
Peter A. Keyel ◽  
Liping Yang ◽  
Jeanette T. Pingel ◽  
Tammy P. Cheng ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Murine Cytomegalovirus ◽  
Cell Tolerance ◽  
Major Histocompatability Complex ◽  
Inhibitory Receptors ◽  
Mcmv Infection ◽  
Functional Defects

Natural killer (NK) cell tolerance mechanisms are incompletely understood. One possibility is that they possess self-specific activation receptors that result in hyporesponsiveness unless modulated by self–major histocompatability complex (MHC)–specific inhibitory receptors. As putative self-specific activation receptors have not been well characterized, we studied a transgenic C57BL/6 mouse that ubiquitously expresses m157 (m157-Tg), which is the murine cytomegalovirus (MCMV)–encoded ligand for the Ly49H NK cell activation receptor. The transgenic mice were more susceptible to MCMV infection and were unable to reject m157-Tg bone marrow, suggesting defects in Ly49H+ NK cells. There was a reversible hyporesponsiveness of Ly49H+ NK cells that extended to Ly49H-independent stimuli. Continuous Ly49H–m157 interaction was necessary for the functional defects. Interestingly, functional defects occurred when mature wild-type NK cells were adoptively transferred to m157-Tg mice, suggesting that mature NK cells may acquire hyporesponsiveness. Importantly, NK cell tolerance caused by Ly49H–m157 interaction was similar in NK cells regardless of expression of Ly49C, an inhibitory receptor specific for a self-MHC allele in C57BL/6 mice. Thus, engagement of self-specific activation receptors in vivo induces an NK cell tolerance effect that is not affected by self-MHC–specific inhibitory receptors.

scholarly journals The Traffic of the NKG2D/Dap10 Receptor Complex during Natural Killer (NK) Cell Activation

2009 ◽  
Vol 284 (24) ◽  
pp. 16463-16472 ◽  
Author(s):  
Pedro Roda-Navarro ◽  
Hugh T. Reyburn
Keyword(s):  
Cell Surface ◽  
Nk Cells ◽  
Cell Activation ◽  
Cell Function ◽  
Nk Cell ◽  
Receptor Expression ◽  
Cell Surface Expression ◽  
Target Cells ◽  
Receptor Complex ◽  
Secretory Lysosomes

NKG2D is an important activating receptor for triggering the NK cell cytotoxic activity, although chronic engagement of specific ligands by NKG2D is also known to provoke decreased cell surface expression of the receptor and compromised NK cell function. We have studied the dynamics of surface NKG2D expression and how exposure to the specific ligand major histocompatibility complex class I chain-related molecule B (MICB) affects receptor traffic and fate. While in the NKL cell line and “resting” NK cells NKG2D was found principally at the cell surface, in activated primary NK cells an intracellular pool of receptor could also be found recycling to the plasma membrane. Exposure of NK cells to targets expressing MICB resulted in degradation of ∼50% of total NKG2D protein and lysosomal degradation of the DAP10 adaptor molecule. Consistent with these observations, confocal microscopy experiments demonstrated that DAP10 trafficked to secretory lysosomes in both transfected NKL cells and in activated primary NK cells upon interaction with MICB-expressing target cells. Interestingly, polarization to the synapse of secretory lysosomes containing DAP10 was also observed. The implications of the intracellular traffic of the NKG2D/DAP10 receptor complex for NK cell activation are discussed. We propose that the rapid degradation of NKG2D/DAP10 observed coincident with recruitment of the receptor to the cytotoxic immune synapse may explain the loss of NKG2D receptor expression after chronic exposure to NKG2D ligands.

scholarly journals NK cells orchestrate splenic cDC1 migration to potentiate antiviral protective CD8+ T cell responses

2020 ◽  
Author(s):  
Sonia Ghilas ◽  
Marc Ambrosini ◽  
Jean-Charles Cancel ◽  
Marion Massé ◽  
Hugues Lelouard ◽  
...  
Keyword(s):  
T Cell ◽  
Nk Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
Murine Cytomegalovirus ◽  
Gm Csf ◽  
Cell Responses ◽  
Infected Cells ◽  
The Right

SummaryA successful immune response relies on a tightly regulated delivery of the right signals to the right cells at the right time. Here we show that innate and innate-like lymphocytes use two mechanisms to orchestrate in time and space the functions of conventional type 1 dendritic cells (cDC1) in spleen. Early after murine cytomegalovirus infection, XCL1 production by lymphocytes with innate functions attracts red pulp cDC1 near IFN-γ-producing NK cells, generating superclusters around infected cells in the marginal zone. There, cDC1 and NK cells physically interact reinforcing their reciprocal activation. Targeted IL-12 delivery and IL-15/IL-15Rα transpresentation by cDC1 trigger NK cell activation and expansion. In return, activated NK cells deliver GM-CSF to cDC1, triggering their CCR7-dependent relocalization into the T cell zone. This NK cell-dependent licensing of cDC1 accelerates the priming of virus-specific CD8+ T cells. Our findings reveal a novel mechanism through which cDC1 bridge innate and adaptive immunity.

scholarly journals IL-2 receptors preassemble and signal in the ER/Golgi causing resistance to antiproliferative anti–IL-2Rα therapies

2019 ◽  
Vol 116 (42) ◽  
pp. 21120-21130 ◽  
Author(s):  
Julianna Volkó ◽  
Ádám Kenesei ◽  
Meili Zhang ◽  
Péter Várnai ◽  
Gábor Mocsár ◽  
...  
Keyword(s):  
T Cell ◽  
Cell Surface ◽  
T Cell Activation ◽  
Cell Activation ◽  
Secretory Pathway ◽  
Interleukin 2 ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Correlation Spectroscopy ◽  
Autocrine Signaling

Interleukin-2 (IL-2) and IL-15 play pivotal roles in T cell activation, apoptosis, and survival, and are implicated in leukemias and autoimmune diseases. Their heterotrimeric receptors share their β- and γc-chains, but have distinct α-chains. Anti–IL-2Rα (daclizumab) therapy targeting cell surface-expressed receptor subunits to inhibit T cell proliferation has only brought limited success in adult T cell leukemia/lymphoma (ATL) and in multiple sclerosis. We asked whether IL-2R subunits could already preassemble and signal efficiently in the endoplasmic reticulum (ER) and the Golgi. A combination of daclizumab and anti–IL-2 efficiently blocked IL-2–induced proliferation of IL-2–dependent wild-type (WT) ATL cells but not cells transfected with IL-2, suggesting that in IL-2–producing cells signaling may already take place before receptors reach the cell surface. In the Golgi fraction isolated from IL-2–producing ATL cells, we detected by Western blot phosphorylated Jak1, Jak3, and a phosphotyrosine signal attributed to the γc-chain, which occurred at much lower levels in the Golgi of WT ATL cells. We expressed EGFP- and mCherry-tagged receptor chains in HeLa cells to study their assembly along the secretory pathway. Confocal microscopy, Förster resonance energy transfer, and imaging fluorescence cross-correlation spectroscopy analysis revealed partial colocalization and molecular association of IL-2 (and IL-15) receptor chains in the ER/Golgi, which became more complete in the plasma membrane, further confirming our hypothesis. Our results define a paradigm of intracellular autocrine signaling and may explain resistance to antagonistic antibody therapies targeting receptors at the cell surface.

scholarly journals GABA acts as a ligand chaperone in the early secretory pathway to promote cell surface expression of GABAA receptors

2010 ◽  
Vol 1346 ◽  
pp. 1-13 ◽  
Author(s):  
Randa S. Eshaq ◽  
Letha D. Stahl ◽  
Randolph Stone ◽  
Sheryl S. Smith ◽  
Lucy C. Robinson ◽  
...  
Keyword(s):  
Cell Surface ◽  
Gabaa Receptors ◽  
Secretory Pathway ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Early Secretory Pathway

scholarly journals Expression of m157, a Murine Cytomegalovirus-Encoded Putative Major Histocompatibility Class I (MHC-I)-Like Protein, Is Independent of Viral Regulation of Host MHC-I

2006 ◽  
Vol 80 (1) ◽  
pp. 545-550 ◽  
Author(s):  
Sandeep K. Tripathy ◽  
Hamish R. C. Smith ◽  
Erika A. Holroyd ◽  
Jeanette T. Pingel ◽  
Wayne M. Yokoyama
Keyword(s):  
Antigen Processing ◽  
Cell Activation ◽  
Nk Cell ◽  
Class I ◽  
Murine Cytomegalovirus ◽  
Viral Gene ◽  
Major Histocompatibility ◽  
Class I Mhc ◽  
Mhc I ◽  
Beta 2 Microglobulin

ABSTRACT A murine cytomegalovirus (MCMV)-encoded protein, m157, has a putative major histocompatibility complex class I (MHC-I) structure and is recognized by the Ly49H NK cell activation receptor. Using a monoclonal antibody against m157, in this study we directly demonstrated that m157 is a cell surface-expressed glycophosphatidylinositol-anchored protein with early viral gene kinetics. Beta-2 microglobulin and TAP1 (transporter associated with antigen processing 1) were not required for its expression. MCMV-encoded proteins that down-regulate MHC-I did not affect the expression of m157. Thus, m157 is expressed on infected cells in a manner independent of viral regulation of host MHC-I.

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