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1.
Sci Immunol ; 7(72): eabn5917, 2022 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-35687698

RESUMO

Although BTB-zinc finger (BTB-ZF) transcription factors control the differentiation of multiple hematopoietic and immune lineages, how they function is poorly understood. The BTB-ZF factor Thpok controls intrathymic CD4+ T cell development and the expression of most CD4+ and CD8+ lineage genes. Here, we identify the nucleosome remodeling and deacetylase (NuRD) complex as a critical Thpok cofactor. Using mass spectrometry and coimmunoprecipitation in primary T cells, we show that Thpok binds NuRD components independently of DNA association. We locate three amino acid residues within the Thpok BTB domain that are required for both NuRD binding and Thpok functions. Conversely, a chimeric protein merging the NuRD component Mta2 to a BTB-less version of Thpok supports CD4+ T cell development, indicating that NuRD recruitment recapitulates the functions of the Thpok BTB domain. We found that NuRD mediates Thpok repression of CD8+ lineage genes, including the transcription factor Runx3, but is dispensable for Cd4 expression. We show that these functions cannot be performed by the BTB domain of the Thpok-related factor Bcl6, which fails to bind NuRD. Thus, cofactor binding critically contributes to the functional specificity of BTB-ZF factors, which control the differentiation of most hematopoietic subsets.


Assuntos
Linfócitos T CD4-Positivos , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase , Diferenciação Celular , Linhagem da Célula , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/metabolismo , Fatores de Transcrição
3.
Nat Immunol ; 18(4): 433-441, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28250424

RESUMO

THEMIS, a T cell-specific protein with high expression in CD4+CD8+ thymocytes, has a crucial role in positive selection and T cell development. THEMIS lacks defined catalytic domains but contains two tandem repeats of a distinctive module of unknown function (CABIT). Here we found that THEMIS directly regulated the catalytic activity of the tyrosine phosphatase SHP-1. This action was mediated by the CABIT modules, which bound to the phosphatase domain of SHP-1 and promoted or stabilized oxidation of SHP-1's catalytic cysteine residue, which inhibited the tyrosine-phosphatase activity of SHP-1. Deletion of SHP-1 alleviated the developmental block in Themis-/- thymocytes. Thus, THEMIS facilitates thymocyte positive selection by enhancing the T cell antigen receptor signaling response to low-affinity ligands.


Assuntos
Seleção Clonal Mediada por Antígeno/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de Sinais , Linfócitos T/imunologia , Linfócitos T/metabolismo , Animais , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Linhagem Celular , Deleção de Genes , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos Knockout , Oxirredução , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteína Tirosina Fosfatase não Receptora Tipo 6/antagonistas & inibidores , Proteína Tirosina Fosfatase não Receptora Tipo 6/química , Proteína Tirosina Fosfatase não Receptora Tipo 6/genética , Espécies Reativas de Oxigênio/metabolismo , Linfócitos T/citologia , Timócitos/citologia , Timócitos/imunologia , Timócitos/metabolismo
4.
Nat Immunol ; 18(2): 205-213, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27992403

RESUMO

The positive and negative selection of lymphocytes by antigen is central to adaptive immunity and self-tolerance, yet how this is determined by different antigens is not completely understood. We found that thymocyte-selection-associated family member 2 (Themis2) increased the positive selection of B1 cells and germinal center B cells by self and foreign antigens. Themis2 lowered the threshold for B-cell activation by low-avidity, but not high-avidity, antigens. Themis2 constitutively bound the adaptor protein Grb2, src-kinase Lyn and signal transducer phospholipase γ2 (PLC-γ2), and increased activation of PLC-γ2 and its downstream pathways following B cell receptor stimulation. Our findings identify a unique function for Themis2 in differential signaling and provide insight into how B cells discriminate between antigens of different quantity and quality.


Assuntos
Linfócitos B/fisiologia , Seleção Clonal Mediada por Antígeno , Centro Germinativo/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Ativação Linfocitária , Imunidade Adaptativa , Animais , Diferenciação Celular , Linhagem da Célula , Células Cultivadas , Proteína Adaptadora GRB2/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Fosfolipase C gama/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Tolerância a Antígenos Próprios , Quinases da Família src/metabolismo
5.
Sci Signal ; 9(428): ra51, 2016 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-27188442

RESUMO

The T cell signaling protein Themis1 is essential for the positive and negative selection of thymocytes in the thymus. Although the developmental defect that results from the loss of Themis1 suggests that it enhances T cell receptor (TCR) signaling, Themis1 also recruits Src homology 2 domain-containing phosphatase-1 (SHP-1) to the vicinity of TCR signaling complexes, suggesting that it has an inhibitory role in TCR signaling. We used TCR signaling reporter mice and quantitative proteomics to explore the role of Themis1 in developing T cells. We found that Themis1 acted mostly as a positive regulator of TCR signaling in vivo when receptors were activated by positively selecting ligands. Proteomic analysis of the Themis1 interactome identified SHP-1, the TCR-associated adaptor protein Grb2, and the guanine nucleotide exchange factor Vav1 as the principal interacting partners of Themis1 in isolated mouse thymocytes. Analysis of TCR signaling in Themis1-deficient and Themis1-overexpressing mouse thymocytes demonstrated that Themis1 promoted Vav1 activity both in vitro and in vivo. The reduced activity of Vav1 and the impaired T cell development in Themis1(-/-) mice were due in part to increased degradation of Grb2, which suggests that Themis1 is required to maintain the steady-state abundance of Grb2 in thymocytes. Together, these data suggest that Themis1 acts as a positive regulator of TCR signaling in developing T cells, and identify a mechanism by which Themis1 regulates thymic selection.


Assuntos
Proteína Adaptadora GRB2/metabolismo , Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-vav/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Timócitos/citologia , Animais , Diferenciação Celular , Peptídeos e Proteínas de Sinalização Intercelular , Ativação Linfocitária , Camundongos , Camundongos Transgênicos , Neuropeptídeos/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Proteômica/métodos , Transdução de Sinais , Transgenes , Proteínas rac1 de Ligação ao GTP/metabolismo
6.
Nat Commun ; 6: 6982, 2015 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-25959494

RESUMO

The T-cell antigen receptor (TCR) complex contains 10 copies of a di-tyrosine Immunoreceptor-Tyrosine-based-Activation-Motif (ITAM) that initiates TCR signalling by recruiting protein tyrosine kinases. ITAM multiplicity amplifies TCR signals, but the importance of this capability for T-cell responses remains undefined. Most TCR ITAMs (6 of 10) are contributed by the CD3ζ subunits. We generated 'knock-in' mice that express non-signalling CD3ζ chains in lieu of wild-type CD3ζ. Here we demonstrate that ITAM multiplicity is important for the development of innate-like T-cells and follicular helper T-cells, events that are known to require strong/sustained TCR-ligand interactions, but is not essential for 'general' T-cell responses including proliferation and cytokine production or for the generation of a diverse antigen-reactive TCR repertoire.


Assuntos
Motivo de Ativação do Imunorreceptor Baseado em Tirosina , Receptores de Antígenos de Linfócitos T/química , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T Auxiliares-Indutores/citologia , Animais , Antígenos/imunologia , Proliferação de Células , Células Clonais , Feminino , Memória Imunológica , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células T Matadoras Naturais/citologia , Células T Matadoras Naturais/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/química , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/química , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Transdução de Sinais , Relação Estrutura-Atividade
7.
Semin Immunol ; 27(6): 388-96, 2015 12.
Artigo em Inglês | MEDLINE | ID: mdl-27040276

RESUMO

Dendritic cells (DCs) are uniquely potent in orchestrating T cell immune response, thus they are indispensable immune sentinels. They originate from progenitors in the bone marrow through hematopoiesis, a highly regulated developmental process involving multiple cellular and molecular events. This review highlights studies of DC development-from the discovery of DCs as glass-adherent antigen presenting cells to the debate and resolution of their origin and lineage map. In particular, we summarize the roles of lineage-specific cytokines, the placement of distinct hematopoietic progenitors within the DC lineage and transcriptional programs governing DC development, which together have allowed us to diagram the current view of DC hematopoiesis. Important open questions and debates on the DC development and relevant models are also discussed.


Assuntos
Células Dendríticas/citologia , Animais , Diferenciação Celular , Linhagem da Célula , Células Dendríticas/imunologia , Hematopoese , Humanos
8.
Immunol Cell Biol ; 92(8): 721-8, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24935457

RESUMO

Thymocyte development requires the coordinated input of signals that originate from numerous cell surface molecules. Although the majority of thymocyte signal-initiating receptors are lineage-specific, most trigger 'ubiquitous' downstream signaling pathways. T-lineage-specific receptors are coupled to these signaling pathways by lymphocyte-restricted adapter molecules. We and others recently identified a new putative adapter protein, Themis1, whose expression is largely restricted to the T lineage. Mice lacking Themis1 exhibit a severe block in thymocyte development and a striking paucity of mature T cells revealing a critical role for Themis1 in T-cell maturation. Themis1 orthologs contain three conserved domains: a proline-rich region (PRR) that binds to the ubiquitous cytosolic adapter Grb2, a nuclear localization sequence (NLS), and two copies of a novel cysteine-containing globular (CABIT) domain. In the present study, we evaluated the functional importance of each of these motifs by retroviral reconstitution of Themis1(-/-) progenitor cells. The results demonstrate an essential requirement for the PRR and NLS motifs but not the conserved CABIT cysteines for Themis1 function.


Assuntos
Domínios e Motivos de Interação entre Proteínas , Proteínas/metabolismo , Timócitos/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Linhagem Celular , Citometria de Fluxo , Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Camundongos , Camundongos Knockout , Dados de Sequência Molecular , Mutação , Fenótipo , Proteínas/química , Proteínas/genética , Timócitos/imunologia , Transdução Genética , Transfecção
9.
J Immunol ; 189(3): 1154-61, 2012 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-22732588

RESUMO

Themis1, a recently identified T cell protein, has a critical function in the generation of mature CD4(+)CD8(-) and CD4(-)CD8(+) (CD4 and CD8 single-positive [SP]) thymocytes and T cells. Although Themis1 has been shown to bind to the adaptor proteins LAT and Grb2, previous studies have yielded conflicting results regarding whether thymocytes from Themis1(-/-) mice exhibit TCR-mediated signaling defects. In this study, we demonstrate that, in the absence of Themis1, TCR-mediated signaling is selectively impaired in CD4 SP and CD8 SP thymocytes but is not affected in CD4(+)CD8(+) double-positive thymocytes despite high expression of Themis1 in double-positive thymocytes. Like Themis1, Themis2, a related member of the Themis family, which is expressed in B cells and macrophages, contains two conserved cysteine-based domains, a proline-rich region, and a nuclear localization signal. To determine whether Themis1 and Themis2 can perform similar functions in vivo, we analyzed T cell development and TCR-mediated signaling in Themis1(-/-) mice reconstituted with either Themis1 or Themis2 transgenes. Notably, Themis1 and Themis2 exhibited the same potential to restore T cell development and TCR-mediated signaling in Themis1(-/-) mice. Both proteins were tyrosine phosphorylated and were recruited within Grb2 signaling complexes to LAT following TCR engagement. These results suggest that conserved molecular features of the Themis1 and Themis2 proteins are important for their biological activity and predict that Themis1 and Themis2 may perform similar functions in T and B cells, respectively.


Assuntos
Diferenciação Celular/imunologia , Sequência Conservada/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Sequência de Aminoácidos , Animais , Células HEK293 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/deficiência , Peptídeos e Proteínas de Sinalização Intracelular/genética , Células Jurkat , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Dados de Sequência Molecular , Coelhos , Linfócitos T/citologia
10.
Rheumatol Int ; 31(8): 1101-3, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21116819

RESUMO

Earlier studies have shown that high doses of TNF-alpha increase apoptosis in human autoimmune T-cell clones. Based on these studies, a treatment approach was proposed to reduce or eliminate autoimmune T cells in patients with type 1 diabetes using drugs that temporarily elevate TNF levels. Here, we report the treatment of ankylosing spondylitis patient with a single high oral dose of Likopid (glucosaminyl-muramyl dipeptide), which aimed at increasing the levels of TNF-alpha in order to induce apoptosis of autoreactive T cells. The flow cytometric analysis of blood samples collected before and after treatment demonstrated massive elimination of CD8(+) T cells. However, the treatment did not result in any notable therapeutic effect, and real-time PCR analysis demonstrated that stably expanded T-cell clones that were earlier tracked in this patient were unaffected. This report suggests that the controversial approach to eliminate autoimmune T-cell clones through overstimulation is not effective in treating ankylosing spondylitis.


Assuntos
Acetilmuramil-Alanil-Isoglutamina/análogos & derivados , Adjuvantes Imunológicos/uso terapêutico , Espondilite Anquilosante/tratamento farmacológico , Acetilmuramil-Alanil-Isoglutamina/uso terapêutico , Adalimumab , Anticorpos Monoclonais Humanizados/uso terapêutico , Antirreumáticos/uso terapêutico , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/patologia , Morte Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Citometria de Fluxo , Humanos , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/patologia , Falha de Tratamento
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