Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Elife ; 112022 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-36519536

RESUMO

The ability to proliferate is a common feature of most T-cell populations. However, proliferation follows different cell-cycle dynamics and is coupled to different functional outcomes according to T-cell subsets. Whether the mitotic machineries supporting these qualitatively distinct proliferative responses are identical remains unknown. Here, we show that disruption of the microtubule-associated protein LIS1 in mouse models leads to proliferative defects associated with a blockade of T-cell development after ß-selection and of peripheral CD4+ T-cell expansion after antigen priming. In contrast, cell divisions in CD8+ T cells occurred independently of LIS1 following T-cell antigen receptor stimulation, although LIS1 was required for proliferation elicited by pharmacological activation. In thymocytes and CD4+ T cells, LIS1 deficiency did not affect signaling events leading to activation but led to an interruption of proliferation after the initial round of division and to p53-induced cell death. Proliferative defects resulted from a mitotic failure, characterized by the presence of extra-centrosomes and the formation of multipolar spindles, causing abnormal chromosomes congression during metaphase and separation during telophase. LIS1 was required to stabilize dynein/dynactin complexes, which promote chromosome attachment to mitotic spindles and ensure centrosome integrity. Together, these results suggest that proliferative responses are supported by distinct mitotic machineries across T-cell subsets.


Assuntos
1-Alquil-2-acetilglicerofosfocolina Esterase , Proteínas Associadas aos Microtúbulos , Linfócitos T , Animais , Camundongos , Linhagem da Célula , Centrossomo/metabolismo , Segregação de Cromossomos , Dineínas/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Mitose , Fuso Acromático/metabolismo
2.
Sci Immunol ; 7(74): eabn6373, 2022 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-35930657

RESUMO

CD2 is largely described to promote T cell activation when engaged by its ligands, CD48 in mice and CD58 in humans, that are present on antigen-presenting cells (APCs). However, both CD48 and CD58 are also expressed on T cells. By generating new knockout mouse strains lacking CD2 or CD48 in the C57BL/6 background, we determined that whereas CD2 was necessary on T cells for T cell activation, its ligand CD48 was not required on APCs. Rather, CD48 was also needed on T cells. One exception was during cytotoxicity, which required CD48 on T cells and APCs. Fluorescence resonance energy transfer (FRET) studies in nonimmune cells provided evidence that cis interactions between CD2 and CD48 existed within individual cells. CD2-CD48 interactions on T cells enabled more robust T cell receptor (TCR) signals, including protein tyrosine phosphorylation. Using T cells from a CD2 knock-in mouse in which a tag was inserted at the carboxyl terminus of CD2, mass spectrometry analyses revealed that the role of CD2 in T cell activation correlated with its ability to interact with components of the TCR complex and the protein tyrosine kinase Lck. CD2-CD58 provided a similar function in human T cells. Thus, our data imply that T cell-intrinsic cis interactions of CD2 with its ligands are required for TCR signaling and T cell activation. Interactions with ligands on APCs contribute during cytotoxicity.


Assuntos
Antígenos CD , Ativação Linfocitária , Linfócitos T , Animais , Antígenos CD2/química , Antígenos CD2/metabolismo , Antígeno CD48/metabolismo , Antígenos CD58/metabolismo , Humanos , Ligantes , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Antígenos de Linfócitos T/metabolismo
3.
J Exp Med ; 218(2)2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33125054

RESUMO

To determine the respective contribution of the LAT transmembrane adaptor and CD5 and CD6 transmembrane receptors to early TCR signal propagation, diversification, and termination, we describe a CRISPR/Cas9-based platform that uses primary mouse T cells and permits establishment of the composition of their LAT, CD5, and CD6 signalosomes in only 4 mo using quantitative mass spectrometry. We confirmed that positive and negative functions can be solely assigned to the LAT and CD5 signalosomes, respectively. In contrast, the TCR-inducible CD6 signalosome comprised both positive (SLP-76, ZAP70, VAV1) and negative (UBASH3A/STS-2) regulators of T cell activation. Moreover, CD6 associated independently of TCR engagement to proteins that support its implication in inflammatory pathologies necessitating T cell transendothelial migration. The multifaceted role of CD6 unveiled here accounts for past difficulties in classifying it as a coinhibitor or costimulator. Congruent with our identification of UBASH3A within the CD6 signalosome and the view that CD6 constitutes a promising target for autoimmune disease treatment, single-nucleotide polymorphisms associated with human autoimmune diseases have been found in the Cd6 and Ubash3a genes.


Assuntos
Antígenos CD/imunologia , Antígenos de Diferenciação de Linfócitos T/imunologia , Ativação Linfocitária/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Linfócitos T/imunologia , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Animais , Doenças Autoimunes/imunologia , Sequência de Bases , Feminino , Inflamação/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Polimorfismo de Nucleotídeo Único/imunologia , Transdução de Sinais/imunologia
4.
J Immunol ; 199(8): 2758-2766, 2017 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-28877990

RESUMO

Themis is a new component of the TCR signaling machinery that plays a critical role during T cell development. The positive selection of immature CD4+CD8+ double-positive thymocytes and their commitment to the CD4+CD8- single-positive stage are impaired in Themis-/- mice, suggesting that Themis might be important to sustain TCR signals during these key developmental processes. However, the analysis of Themis mRNA levels revealed that Themis gene expression is rapidly extinguished during positive selection. We show in this article that Themis protein expression is increased in double-positive thymocytes undergoing positive selection and is sustained in immature single-positive thymocytes, despite the strong decrease in Themis mRNA levels in these subsets. We found that Themis stability is controlled by the ubiquitin-specific protease USP9X, which removes ubiquitin K48-linked chains on Themis following TCR engagement. Biochemical analyses indicate that USP9X binds directly to the N-terminal CABIT domain of Themis and indirectly to the adaptor protein Grb2, with the latter interaction enabling recruitment of Themis/USP9X complexes to LAT, thereby sustaining Themis expression following positive selection. Together, these data suggest that TCR-mediated signals enhance Themis stability upon T cell development and identify USP9X as a key regulator of Themis protein turnover.


Assuntos
Endopeptidases/metabolismo , Células Precursoras de Linfócitos T/fisiologia , Proteínas/metabolismo , Linfócitos T/fisiologia , Timo/imunologia , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Diferenciação Celular , Células Cultivadas , Seleção Clonal Mediada por Antígeno , Proteína Adaptadora GRB2/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular , Ativação Linfocitária , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfoproteínas/metabolismo , Ligação Proteica , Estabilidade Proteica , Proteínas/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Ubiquitina Tiolesterase
6.
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
7.
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
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...