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1.
Emerg Microbes Infect ; 8(1): 734-748, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31130074

RESUMO

Many pathogens infect hosts through various immune evasion strategies. However, the molecular mechanisms by which pathogen proteins modulate and evade the host immune response remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a pathological strain that can induce mitogen-activated protein (MAP) kinase (Erk, Jnk and p38 MAPK) and NF-κB pathway activation and proinflammatory cytokine production, which then causes diarrheal diseases such as hemorrhagic colitis and hemolytic uremic syndrome. Transforming growth factor ß-activated kinase-1 (TAK1) is a key regulator involved in distinct innate immune signalling pathways. Here we report that EHEC translocated intimin receptor (Tir) protein inhibits the expression of EHEC-induced proinflammatory cytokines by interacting with the host tyrosine phosphatase SHP-1, which is dependent on the phosphorylation of immunoreceptor tyrosine-based inhibition motifs (ITIMs). Mechanistically, the association of EHEC Tir with SHP-1 facilitated the recruitment of SHP-1 to TAK1 and inhibited TAK1 phosphorylation, which then negatively regulated K63-linked polyubiquitination of TAK1 and downstream signal transduction. Taken together, these results suggest that EHEC Tir negatively regulates proinflammatory responses by inhibiting the activation of TAK1, which is essential for immune evasion and could be a potential target for the treatment of bacterial infection.


Assuntos
Escherichia coli Êntero-Hemorrágica/patogenicidade , Infecções por Escherichia coli/fisiopatologia , Proteínas de Escherichia coli/metabolismo , Interações Hospedeiro-Patógeno , Evasão da Resposta Imune , MAP Quinase Quinase Quinases/antagonistas & inibidores , Receptores de Superfície Celular/metabolismo , Fatores de Virulência/metabolismo , Animais , Infecções por Escherichia coli/microbiologia , Células HEK293 , Humanos , Macrófagos Peritoneais , Camundongos , Camundongos Endogâmicos C57BL , Ligação Proteica , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Células RAW 264.7
2.
Nat Commun ; 10(1): 746, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-30765691

RESUMO

Excessive or uncontrolled release of proinflammatory cytokines caused by severe viral infections often results in host tissue injury or even death. Phospholipase C (PLC)s degrade phosphatidylinositol-4, 5-bisphosphate (PI(4,5)P2) lipids and regulate multiple cellular events. Here, we report that PLCß2 inhibits the virus-induced expression of pro-inflammatory cytokines by interacting with and inhibiting transforming growth factor-ß-activated kinase 1 (TAK1) activation. Mechanistically, PI(4,5)P2 lipids directly interact with TAK1 at W241 and N245, and promote its activation. Impairing of PI(4,5)P2's binding affinity or mutation of PIP2-binding sites on TAK1 abolish its activation and the subsequent production of pro-inflammatory cytokines. Moreover, PLCß2-deficient mice exhibit increased expression of proinflammatory cytokines and a higher frequency of death in response to virus infection, while the PLCß2 activator, m-3M3FBS, protects mice from severe Coxsackie virus A 16 (CVA16) infection. Thus, our findings suggest that PLCß2 negatively regulates virus-induced pro-inflammatory responses by inhibiting phosphoinositide-mediated activation of TAK1.


Assuntos
Infecções por Coxsackievirus/metabolismo , Citocinas/metabolismo , MAP Quinase Quinase Quinases/metabolismo , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfolipase C beta/metabolismo , Animais , Células Cultivadas , Cercopithecus aethiops , Infecções por Coxsackievirus/genética , Infecções por Coxsackievirus/virologia , Citocinas/genética , Enterovirus/fisiologia , Ativação Enzimática , Regulação da Expressão Gênica , Células HEK293 , Humanos , MAP Quinase Quinase Quinases/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfolipase C beta/genética , Ligação Proteica , Células Vero
3.
Nature ; 563(7729): 131-136, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30356214

RESUMO

Accurate repair of DNA double-stranded breaks by homologous recombination preserves genome integrity and inhibits tumorigenesis. Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor that activates innate immunity by initiating the STING-IRF3-type I IFN signalling cascade1,2. Recognition of ruptured micronuclei by cGAS links genome instability to the innate immune response3,4, but the potential involvement of cGAS in DNA repair remains unknown. Here we demonstrate that cGAS inhibits homologous recombination in mouse and human models. DNA damage induces nuclear translocation of cGAS in a manner that is dependent on importin-α, and the phosphorylation of cGAS at tyrosine 215-mediated by B-lymphoid tyrosine kinase-facilitates the cytosolic retention of cGAS. In the nucleus, cGAS is recruited to double-stranded breaks and interacts with PARP1 via poly(ADP-ribose). The cGAS-PARP1 interaction impedes the formation of the PARP1-Timeless complex, and thereby suppresses homologous recombination. We show that knockdown of cGAS suppresses DNA damage and inhibits tumour growth both in vitro and in vivo. We conclude that nuclear cGAS suppresses homologous-recombination-mediated repair and promotes tumour growth, and that cGAS therefore represents a potential target for cancer prevention and therapy.

4.
Clin Immunol ; 194: 1-8, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29906512

RESUMO

Increasing rates of life-threatening infections and decreasing susceptibility to antibiotics urge an effective vaccine targeting Staphylococcus aureus. Here we investigate the role of cellular immunity in FnBPA110-263 mediated protection in Staphylococcus aureus infection. This study revealed FnBPA110-263 broadly protected mice from seven FnBPA isotypes strains in the sepsis model. FnBPA110-263 immunized B-cell deficient mice were protected against lethal challenge, while T-cell deficient mice were not. Reconstituting mice with FnBPA110-263 specific CD4+ T-cells conferred antigen specific protection. In vitro assays indicated that isolated FnBPA110-263 specific splenocytes from immunized mice produced abundant IL-17A. IL-17A deficient mice were not protected from a lethal challenge by FnBPA110-263 vaccination. Moreover, neutralizing IL-17A, but not IFN-γ,reverses FnBPA110-263-induced protective efficacy in sepsis and skin infection model. These findings suggest that IL-17A producing Th17 cells play an essential role in FnBPA110-263 vaccine-mediated defense against S. aureus sepsis and skin infection in mice.

5.
Sci Rep ; 8(1): 3603, 2018 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-29483608

RESUMO

Macrophages are important innate immune defense system cells in the fight against bacterial and fungal pathogenic infections. They exhibit significant plasticity, particularly with their ability to undergo functional differentiation. Additionally, HIF1α is critically involved in the functional differentiation of macrophages during inflammation. However, the role of macrophage HIF1α in protecting against different pathogenic infections remains unclear. In this study, we investigated and compared the roles of HIF1α in different macrophage functional effects of bacterial and fungal infections in vitro and in vivo. We found that bacterial and fungal infections produced similar effects on macrophage functional differentiation. HIF1α deficiency inhibited pro-inflammatory macrophage functional activities when cells were stimulated with LPS or curdlan in vitro or when mice were infected with L. monocytogenes or C. albicans in vivo, thus decreasing pro-inflammatory TNFα and IL-6 secretion associated with pathogenic microorganism survival. Alteration of glycolytic pathway activation was required for the functional differentiation of pro-inflammatory macrophages in protecting against bacterial and fungal infections. Thus, the HIF1α-dependent glycolytic pathway is essential for pro-inflammatory macrophage functional differentiation in protecting against bacterial and fungal infections.

6.
J Infect Dis ; 218(2): 312-323, 2018 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-29228365

RESUMO

Tuberculosis, caused by Mycobacterium tuberculosis infection, remains a global threat to human health, but knowledge of the molecular mechanisms underlying the pathogenesis of tuberculosis is still limited. Although Notch4, a member of the Notch receptor family, is involved in the initiation of mammary tumors, its function in M. tuberculosis infection remains unclear. In this study, we found that Notch4-deficient mice were more resistant to M. tuberculosis infection, with a much lower bacterial burden and fewer pathological changes in the lungs. Notch4 inhibited M. tuberculosis-induced production of proinflammatory cytokines by interaction with TAK1 and inhibition of its activation. Furthermore, we found that Notch intracellular domain 4 prevented TRAF6 autoubiquitination and suppressed TRAF6-mediated TAK1 polyubiquitination. Finally, Notch inhibitors made mice more resistant to M. tuberculosis infection. These results suggest that Notch4 is a negative regulator of M. tuberculosis-induced inflammatory response, and treatment with a Notch inhibitor could serve as a new therapeutic strategy for tuberculosis.

7.
Adv Exp Med Biol ; 1024: 37-61, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28921464

RESUMO

Inflammation is usually the defensive reaction of the immune system to the invasion of pathogen and the exogenous objects. The activation of inflammation helps our body to eliminate pathogenic microbe, virus, and parasite harming our health, while under many circumstances inflammation is the direct cause of the pathological damage in tissues and dysfunction of organs. The posttranslational modification (PTM) of the inflammatory pathways, such as TLR pathways, RLR pathways, NLR pathway, intracellular DNA sensors, intracellular RNA sensors, and inflammasomes, is crucial in the regulation of these signaling trails. Ubiquitination, phosphorylation, polyubiquitination, methylation, and acetylation are the main forms of the PTM, and they respectively play different roles in signaling regulation. The effects of the PTM range from the production of pro-inflammatory factors and the interaction between adaptors and receptors to cell translocation in response to the infectious or other dangerous factors. In this chapter, we will have an overview of the different ways of the posttranslational modifications in different inflammatory signaling pathways and their essential roles in regulation of inflammation.


Assuntos
Regulação da Expressão Gênica/imunologia , Inflamação/metabolismo , Processamento de Proteína Pós-Traducional/imunologia , Transdução de Sinais/imunologia , Animais , Proteína DEAD-box 58/genética , Proteína DEAD-box 58/metabolismo , Regulação da Expressão Gênica/fisiologia , Humanos , Inflamassomos , Inflamação/imunologia , Proteínas NLR/genética , Proteínas NLR/metabolismo , Nucleotidiltransferases/genética , Nucleotidiltransferases/metabolismo , Fosforilação , RNA/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Receptores Toll-Like/imunologia , Ubiquitinação
8.
PLoS Pathog ; 13(6): e1006436, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28622363

RESUMO

Pulmonary infection is the most common risk factor for acute lung injury (ALI). Innate immune responses induced by Microbe-Associated Molecular Pattern (MAMP) molecules are essential for lung defense but can lead to tissue injury. Little is known about how MAMP molecules are degraded in the lung or how MAMP degradation/inactivation helps prevent or ameliorate the harmful inflammation that produces ALI. Acyloxyacyl hydrolase (AOAH) is a host lipase that inactivates Gram-negative bacterial endotoxin (lipopolysaccharide, or LPS). We report here that alveolar macrophages increase AOAH expression upon exposure to LPS and that Aoah+/+ mice recover more rapidly than do Aoah-/- mice from ALI induced by nasally instilled LPS or Klebsiella pneumoniae. Aoah-/- mouse lungs had more prolonged leukocyte infiltration, greater pro- and anti-inflammatory cytokine expression, and longer-lasting alveolar barrier damage. We also describe evidence that the persistently bioactive LPS in Aoah-/- alveoli can stimulate alveolar macrophages directly and epithelial cells indirectly to produce chemoattractants that recruit neutrophils to the lung and may prevent their clearance. Distinct from the prolonged tolerance observed in LPS-exposed Aoah-/- peritoneal macrophages, alveolar macrophages that lacked AOAH maintained or increased their responses to bioactive LPS and sustained inflammation. Inactivation of LPS by AOAH is a previously unappreciated mechanism for promoting resolution of pulmonary inflammation/injury induced by Gram-negative bacterial infection.


Assuntos
Lesão Pulmonar Aguda/imunologia , Hidrolases de Éster Carboxílico/imunologia , Lipopolissacarídeos/efeitos adversos , Lesão Pulmonar Aguda/enzimologia , Lesão Pulmonar Aguda/etiologia , Animais , Hidrolases de Éster Carboxílico/genética , Humanos , Infecções por Klebsiella/enzimologia , Infecções por Klebsiella/genética , Infecções por Klebsiella/imunologia , Klebsiella pneumoniae/imunologia , Lipopolissacarídeos/imunologia , Pulmão/imunologia , Pulmão/microbiologia , Macrófagos Peritoneais/enzimologia , Macrófagos Peritoneais/imunologia , Camundongos , Camundongos Knockout
9.
Cell Mol Immunol ; 14(3): 237-244, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27796284

RESUMO

To successfully infect host cells and evade the host immune response, a type III secretion system (T3SS) is commonly used by enteric bacterial pathogens such as enteropathogenic Escherichia coli (EPEC). Recent findings have revealed that various effectors are injected into host cells through the T3SS and exert an inhibitory effect on inflammatory signaling pathways, subverting the immune responses to these pathogens. Here we review recent studies aimed at addressing the modulation of several important inflammatory signaling pathways modulated by EPEC effector proteins, such as the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) pathways, which provides insight into the unfinished work in this unexplored field and helps to identify novel positions in inflammatory signaling networks for EPEC effectors.Cellular & Molecular Immunology advance online publication, 31 October 2016; doi:10.1038/cmi.2016.52.


Assuntos
Escherichia coli Enteropatogênica/patogenicidade , Proteínas de Escherichia coli/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Inflamação/microbiologia , Transdução de Sinais , Fatores de Virulência/metabolismo , Animais , Humanos , Inflamação/patologia
10.
Opt Express ; 24(13): 14463-9, 2016 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-27410599

RESUMO

We report a high power all-fiber amplifier with suitable seed power injected by an all-fiber laser. Different seed powers were injected into the all-fiber amplifier during our amplification experiments, and we found the stimulated Raman scattering (SRS) threshold was inversely proportional to the injected seed power. More than 3 kW signal light with good beam quality (M2 = 1.28) has been obtained with a suitable seed power injected, and the slope efficiency of the all-fiber amplifier was about 84.4%.

11.
Nat Immunol ; 17(4): 397-405, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26928339

RESUMO

The signaling adaptor TRAF3 is a highly versatile regulator of both innate immunity and adaptive immunity, but how its phosphorylation is regulated is still unknown. Here we report that deficiency in or inhibition of the conserved serine-threonine kinase CK1ɛ suppressed the production of type I interferon in response to viral infection. CK1ɛ interacted with and phosphorylated TRAF3 at Ser349, which thereby promoted the Lys63 (K63)-linked ubiquitination of TRAF3 and subsequent recruitment of the kinase TBK1 to TRAF3. Consequently, CK1ɛ-deficient mice were more susceptible to viral infection. Our findings establish CK1ɛ as a regulator of antiviral innate immune responses and indicate a novel mechanism of immunoregulation that involves CK1ɛ-mediated phosphorylation of TRAF3.


Assuntos
Caseína Quinase Iépsilon/imunologia , Imunidade Inata/imunologia , Interferon beta/imunologia , Fator 3 Associado a Receptor de TNF/imunologia , Animais , Caseína Quinase Iépsilon/antagonistas & inibidores , Caseína Quinase Iépsilon/genética , Ensaio de Imunoadsorção Enzimática , Células HEK293 , Células HeLa , Herpes Simples/imunologia , Herpesvirus Humano 1/imunologia , Humanos , Interferon Tipo I/biossíntese , Interferon Tipo I/imunologia , Interferon beta/biossíntese , Espectrometria de Massas , Camundongos , Camundongos Knockout , Fosforilação , Proteínas Serina-Treonina Quinases , Reação em Cadeia da Polimerase em Tempo Real , Infecções por Rhabdoviridae/imunologia , Fator 3 Associado a Receptor de TNF/genética , Ubiquitinação , Vesiculovirus/imunologia , Febre do Nilo Ocidental/imunologia , Vírus do Nilo Ocidental/imunologia
12.
Proc Natl Acad Sci U S A ; 112(48): 14942-7, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26627244

RESUMO

FoxP3(+) T regulatory (Treg) cells have a fundamental role in immunological tolerance, with transcriptional and functional phenotypes that demarcate them from conventional CD4(+) T cells (Tconv). Differences between these two lineages in the signaling downstream of T-cell receptor-triggered activation have been reported, and there are different requirements for some signaling factors. Seeking a comprehensive view, we found that Treg cells have a broadly dampened activation of several pathways and signaling nodes upon TCR-mediated activation, with low phosphorylation of CD3ζ, SLP76, Erk1/2, AKT, or S6 and lower calcium flux. In contrast, STAT phosphorylation triggered by interferons, IL2 or IL6, showed variations between Treg and Tconv in magnitude or choice of preferential STAT activation but no general Treg signaling defect. Much, but not all, of the Treg/Tconv difference in TCR-triggered responses could be attributed to lower responsiveness of antigen-experienced cells with CD44(hi) or CD62L(lo) phenotypes, which form a greater proportion of the Treg pool. Candidate regulators were tested, but the Treg/Tconv differential could not be explained by overexpression in Treg cells of the signaling modulator CD5, the coinhibitors PD-1 and CTLA4, or the regulatory phosphatase DUSP4. However, transcriptome profiling in Dusp4-deficient mice showed that DUSP4 enhances the expression of a segment of the canonical Treg transcriptional signature, which partially overlaps with the TCR-dependent Treg gene set. Thus, Treg cells, likely because of their intrinsically higher reactivity to self, tune down TCR signals but seem comparatively more attuned to cytokines or other intercellular signals.


Assuntos
Sinalização do Cálcio/imunologia , Fatores de Transcrição Forkhead/imunologia , Regulação da Expressão Gênica/imunologia , Sistema de Sinalização das MAP Quinases/imunologia , Linfócitos T Reguladores/imunologia , Animais , Antígenos CD/genética , Antígenos CD/imunologia , Antígeno CTLA-4/genética , Antígeno CTLA-4/imunologia , Sinalização do Cálcio/genética , Fatores de Transcrição Forkhead/genética , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Knockout , Proteína Quinase 3 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/imunologia , Receptor de Morte Celular Programada 1/genética , Receptor de Morte Celular Programada 1/imunologia , Proteínas Tirosina Fosfatases/genética , Proteínas Tirosina Fosfatases/imunologia , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/imunologia , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia
13.
Cell Signal ; 25(9): 1887-94, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23707390

RESUMO

Immune responses to pathogens are regulated by immune receptors containing either an immunoreceptor tyrosine-based activation motif (ITAM) or an immunoreceptor tyrosine-based inhibitory motif (ITIM). The important diarrheal pathogen enteropathogenic Escherichia coli (EPEC) require delivery and insertion of the bacterial translocated intimin receptor (Tir) into the host plasma membrane for pedestal formation. The C-terminal region of Tir, encompassing Y483 and Y511, shares sequence similarity with cellular ITIMs. Here, we show that EPEC Tir suppresses the production of inflammatory cytokines by recruitment of SHP-2 and subsequent deubiquitination of TRAF6 in an ITIM dependent manner. Our findings revealed a novel mechanism by which the EPEC utilize its ITIM motifs to suppress and evade the host innate immune response, which could lead to the development of novel therapeutics to prevent bacterial infection.


Assuntos
Escherichia coli Enteropatogênica/fisiologia , Infecções por Escherichia coli/imunologia , Proteínas de Escherichia coli/imunologia , Interações Hospedeiro-Parasita , Motivo de Ativação do Imunorreceptor Baseado em Tirosina , Proteína Tirosina Fosfatase não Receptora Tipo 11/imunologia , Receptores de Superfície Celular/imunologia , Animais , Linhagem Celular , Citocinas/imunologia , Infecções por Escherichia coli/metabolismo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação , Ligação Proteica , Mapas de Interação de Proteínas , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Receptores de Superfície Celular/química , Receptores de Superfície Celular/metabolismo , Fator 6 Associado a Receptor de TNF/metabolismo , Ubiquitinação
14.
Nat Immunol ; 13(11): 1063-71, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23001144

RESUMO

The protein Tir (translocated intimin receptor) in enteric bacteria shares sequence similarity with the host cellular immunoreceptor tyrosine-based inhibition motifs (ITIMs). Despite the importance of Tir in pedestal formation, relatively little is known about the role of Tir and its ITIMs in the regulation of the host immune response. Here we demonstrate that Tir from enteropathogenic Escherichia coli (EPEC) interacted with the host cellular tyrosine phosphatase SHP-1 in an ITIM phosphorylation-dependent manner. The association of Tir with SHP-1 facilitated the recruitment of SHP-1 to the adaptor TRAF6 and inhibited the ubiquitination of TRAF6. Moreover, the ITIMs of Tir suppressed EPEC-stimulated expression of proinflammatory cytokines and inhibited intestinal immunity to infection with Citrobacter rodentium. Our findings identify a previously unknown mechanism by which bacterial ITIM-containing proteins can inhibit innate immune responses.


Assuntos
Infecções por Enterobacteriaceae/imunologia , Proteínas de Escherichia coli/imunologia , Motivo de Inibição do Imunorreceptor Baseado em Tirosina/imunologia , Intestinos/imunologia , Receptores de Superfície Celular/imunologia , Transdução de Sinais/imunologia , Animais , Células Cultivadas , Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/genética , Infecções por Enterobacteriaceae/microbiologia , Escherichia coli Enteropatogênica/imunologia , Escherichia coli Enteropatogênica/patogenicidade , Proteínas de Escherichia coli/genética , Regulação da Expressão Gênica/imunologia , Interações Hospedeiro-Patógeno , Imunidade Inata , Imunidade nas Mucosas , Motivo de Inibição do Imunorreceptor Baseado em Tirosina/genética , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Intestinos/microbiologia , Macrófagos/imunologia , Macrófagos/microbiologia , Camundongos , Fosforilação , Ligação Proteica , Proteína Tirosina Fosfatase não Receptora Tipo 6/genética , Proteína Tirosina Fosfatase não Receptora Tipo 6/imunologia , Receptores de Superfície Celular/genética , Transdução de Sinais/genética , Fator 6 Associado a Receptor de TNF/genética , Fator 6 Associado a Receptor de TNF/imunologia , Ubiquitina/genética , Ubiquitina/imunologia , Ubiquitinação
15.
Cell Signal ; 23(2): 487-96, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21070852

RESUMO

Inhibitory signaling is crucial in the regulation of the cytotoxicity of natural killer (NK) cells. Here, we show that KIR2DL1, an inhibitory receptor of NK cells, associates with supervillin, an F-actin binding protein. Interaction of supervillin with KIR2DL1 is dependent on the KIR2DL1 receptor stimulation and requires the phosphorylation of tyrosines in both ITIM motifs. "Knockdown" of expression of supervillin by RNA interference (RNAi) restores the KIR2DL1-suppressed cytotoxicity of NK cells. Inhibition of supervillin by RNAi also enhances the polarization of cytolytic granules (both granzyme B and perforin) to the synapse formed between YTS-GFP-KIR2DL1 NK cells and 721.221-HLA-Cw4 target cells. Further study reveals that supervillin is required for KIR2DL1-mediated inhibition of Vav1 and ERK phoshorylation. Moreover, we have found that binding of supervillin with KIR2DL1 facilitates the recruitment of SHPs especially SHP-2 to KIR2DL1 receptor. Thus, our findings demonstrate that supervillin is a novel molecule that associates with KIR2DL1 receptor and regulates the inhibitory signaling in NK cells.


Assuntos
Células Matadoras Naturais/fisiologia , Proteínas de Membrana/metabolismo , Proteínas dos Microfilamentos/metabolismo , Receptores KIR2DL1/metabolismo , Transdução de Sinais , Motivos de Aminoácidos , Linhagem Celular Transformada , Sequência Consenso , Citotoxicidade Imunológica , Células HEK293 , Humanos , Células Matadoras Naturais/imunologia , Proteínas de Membrana/genética , Proteínas dos Microfilamentos/genética , Fosforilação , Ligação Proteica , Transporte Proteico , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Interferência de RNA , Células Tumorais Cultivadas
16.
Cell Signal ; 20(11): 2002-12, 2008 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18713649

RESUMO

The adaptor protein paxillin plays an important role in cell migration. Although the c-Jun amino-terminal kinase (JNK) phosphorylation of paxillin on Ser 178 has been found to be critical for cell migration, the precise mechanism by which JNK regulates cell migration is still not very clear. Here, the migration of human corneal epithelial (HCE) cells was used to determine which signaling pathways are involved in EGF-induced paxillin phosphorylation. Paxillin was phosphorylated on Tyr 31 and Tyr 118 after induction of migration by EGF in HCE cells. Specific inhibition of JNK activation by inhibitor SP600125 or overexpression of a dominant-negative JNK mutant not only blocked EGF-induced cell migration, but also eliminated tyrosine phosphorylation of paxillin on Tyr 31 and Tyr 118. HCE cells overexpressing paxillin-S178A mutant also exhibited lower mobility, and reduced phosphorylation of Tyr 31 and Tyr 118. However, paxillin-S178A-inhibited cell migration can be rescued by overexpression of paxillin-Y31E/Y118E mutant. Importantly, inhibition of JNK by SP600125 or overexpression of paxillin-S178A mutant prevented the association of FAK with paxillin. Taken together, these results suggest that phosphorylation of paxillin on Ser 178 by JNK is required for the association of paxillin with FAK, and subsequent tyrosine phosphorylation of paxillin.


Assuntos
Movimento Celular , Células Epiteliais/citologia , Epitélio Anterior/citologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Paxilina/metabolismo , Fosfotirosina/metabolismo , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Fator de Crescimento Epidérmico/farmacologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/enzimologia , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Modelos Biológicos , Proteínas Mutantes/metabolismo , Fosforilação/efeitos dos fármacos , Fosfosserina/metabolismo
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