Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Leuk Res ; 35(8): 1111-3, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21497902

RESUMO

The expression of drebrin, a cytoskeletal protein newly estimated by expression profiling to correlate with the genotype and prognosis of B-cell precursor acute lymphoblastic leukemia (BCP-ALL), was examined by independent methods. After demonstrating its higher expression in TEL/AML1(pos) BCP-ALL by quantitative reverse transcriptase polymerase chain reaction, we developed an anti-drebrin monoclonal antibody (mAb). In a cohort of 86 children with BCP-ALL, we found increased expression of drebrin in TEL/AML1(pos) ALL. In conclusion, relationship of drebrin expression and prognosis or genotype can now be assessed using flow cytometry.


Assuntos
Anticorpos Monoclonais/imunologia , Neuropeptídeos/imunologia , Neuropeptídeos/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras B/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Doença Aguda , Animais , Subunidade alfa 2 de Fator de Ligação ao Core , Citometria de Fluxo , Humanos , Camundongos , Proteínas de Fusão Oncogênica , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Prognóstico , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
2.
J Immunol ; 179(8): 5169-80, 2007 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-17911602

RESUMO

Engagement of the FcepsilonRI in mast cells and basophils leads to a rapid tyrosine phosphorylation of the transmembrane adaptors LAT (linker for activation of T cells) and NTAL (non-T cell activation linker, also called LAB or LAT2). NTAL regulates activation of mast cells by a mechanism, which is incompletely understood. Here we report properties of rat basophilic leukemia cells with enhanced or reduced NTAL expression. Overexpression of NTAL led to changes in cell morphology, enhanced formation of actin filaments and inhibition of the FcepsilonRI-induced tyrosine phosphorylation of the FcepsilonRI subunits, Syk kinase and LAT and all downstream activation events, including calcium and secretory responses. In contrast, reduced expression of NTAL had little effect on early FcepsilonRI-induced signaling events but inhibited calcium mobilization and secretory response. Calcium response was also repressed in Ag-activated cells defective in Grb2, a major target of phosphorylated NTAL. Unexpectedly, in cells stimulated with thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+) ATPase, the amount of cellular NTAL directly correlated with the uptake of extracellular calcium even though no enhanced tyrosine phosphorylation of NTAL was observed. The combined data indicate that NTAL regulates FcepsilonRI-mediated signaling at multiple steps and by different mechanisms. At early stages NTAL interferes with tyrosine phosphorylation of several substrates and formation of signaling assemblies, whereas at later stages it regulates the activity of store-operated calcium channels through a distinct mechanism independent of enhanced NTAL tyrosine phosphorylation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sistema y+ de Transporte de Aminoácidos/fisiologia , Sinalização do Cálcio/imunologia , Cadeias Leves da Proteína-1 Reguladora de Fusão/fisiologia , Mastócitos/imunologia , Mastócitos/metabolismo , Tirosina/metabolismo , Sequência de Aminoácidos , Animais , Cálcio/metabolismo , Linhagem Celular Tumoral , Líquido Intracelular/metabolismo , Dados de Sequência Molecular , Fosforilação , Ratos , Receptores de IgE/fisiologia
3.
Nucleic Acids Res ; 35(8): 2748-58, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17426121

RESUMO

LAGLIDADG homing endonucleases (LHEs) cleave 18-24 bp DNA sequences and are promising enzymes for applications requiring sequence-specific DNA cleavage amongst genome-sized DNA backgrounds. Here, we report a method for cell surface display of LHEs, which facilitates analysis of their DNA binding and cleavage properties by flow cytometry. Cells expressing surface LHEs can be stained with fluorescently conjugated double-stranded oligonucleotides (dsOligos) containing their respective target sequences. The signal is absolutely sequence specific and undetectable with dsOligos carrying single base-pair substitutions. LHE-dsOligo interactions facilitate rapid enrichment and viable recovery of rare LHE expressing cells by both fluorescence-activated cell sorting (FACS) and magnetic cell sorting (MACS). Additionally, dsOligos conjugated with unique fluorophores at opposite termini can be tethered to the cell surface and used to detect DNA cleavage. Recapitulation of DNA binding and cleavage by surface-displayed LHEs provides a high-throughput approach to library screening that should facilitate rapid identification and analysis of enzymes with novel sequence specificities.


Assuntos
Membrana Celular/enzimologia , Proteínas de Ligação a DNA/análise , Endodesoxirribonucleases/análise , Citometria de Fluxo/métodos , Animais , Linhagem Celular , Separação Celular , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Endodesoxirribonucleases/genética , Endodesoxirribonucleases/metabolismo , Corantes Fluorescentes , Magnetismo , Sondas de Oligonucleotídeos , Proteínas Recombinantes/análise , Especificidade por Substrato
4.
J Exp Med ; 200(8): 1001-13, 2004 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-15477348

RESUMO

Engagement of the Fcepsilon receptor I (FcepsilonRI) on mast cells and basophils initiates signaling pathways leading to degranulation. Early activation events include tyrosine phosphorylation of two transmembrane adaptor proteins, linker for activation of T cells (LAT) and non-T cell activation linker (NTAL; also called LAB; a product of Wbscr5 gene). Previous studies showed that the secretory response was partially inhibited in bone marrow-derived mast cells (BMMCs) from LAT-deficient mice. To clarify the role of NTAL in mast cell degranulation, we compared FcepsilonRI-mediated signaling events in BMMCs from NTAL-deficient and wild-type mice. Although NTAL is structurally similar to LAT, antigen-mediated degranulation responses were unexpectedly increased in NTAL-deficient mast cells. The earliest event affected was enhanced tyrosine phosphorylation of LAT in antigen-activated cells. This was accompanied by enhanced tyrosine phosphorylation and enzymatic activity of phospholipase C gamma1 and phospholipase C gamma2, resulting in elevated levels of inositol 1,4,5-trisphosphate and free intracellular Ca2+. NTAL-deficient BMMCs also exhibited an enhanced activity of phosphatidylinositol 3-OH kinase and Src homology 2 domain-containing protein tyrosine phosphatase-2. Although both LAT and NTAL are considered to be localized in membrane rafts, immunogold electron microscopy on isolated membrane sheets demonstrated their independent clustering. The combined data show that NTAL is functionally and topographically different from LAT.


Assuntos
Proteínas Adaptadoras de Transporte Vesicular/fisiologia , Mastócitos/fisiologia , Proteínas/fisiologia , Transdução de Sinais , Proteínas Adaptadoras de Transdução de Sinal/fisiologia , Animais , Cálcio/metabolismo , Degranulação Celular , Proteínas de Membrana/fisiologia , Camundongos , Fosfatidilinositol 3-Quinases/fisiologia , Fosfolipase C gama , Fosfoproteínas/fisiologia , Fosforilação , Receptores de IgE/fisiologia , Fosfolipases Tipo C/metabolismo , Tirosina/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...