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1.
J Biol Chem ; 276(25): 23009-17, 2001 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-11294831

RESUMO

The MAL proteolipid, an integral protein present in glycolipid- and cholesterol-enriched membrane (GEM) rafts, is an element of the machinery necessary for apical sorting in polarized epithelial Madin-Darby canine kidney cells. MAL was the first member identified of an extended family of proteins that have significant overall sequence identity. In this study we have used a newly generated monoclonal antibody to investigate an unedited member of this family, named BENE, which was found to be expressed in endothelial-like ECV304 cells and normal human endothelium. Human BENE was characterized as a proteolipid protein predominantly present in GEM rafts in ECV304 cells. Coimmunoprecipitation experiments revealed that BENE interacted with caveolin-1. Confocal immunofluorescence and electron microscopic analyses indicated that BENE mainly accumulated into intracellular vesicular/tubular structures that partially colocalize with internal caveolin-1. In response to cell surface cholesterol oxidation, BENE redistributed to the dilated vesicular structures that concentrate most of the caveolin-1 originally on the cell surface. After cessation of cholesterol oxidation, a detectable fraction of the BENE molecules migrated to the plasmalemma accompanying caveolin-1 and then returned progressively to its steady state distribution. Together, these features highlight the BENE proteolipid as being an element of the machinery for raft-mediated trafficking in endothelial cells.


Assuntos
Proteínas de Transporte/metabolismo , Caveolinas/metabolismo , Endotélio/metabolismo , Proteínas de Membrana/metabolismo , Proteolipídeos/metabolismo , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Proteínas de Transporte/química , Proteínas de Transporte/genética , Proteínas de Transporte/imunologia , Bovinos , Caveolina 1 , Linhagem Celular , Colesterol/metabolismo , Endotélio/citologia , Endotélio/ultraestrutura , Regulação da Expressão Gênica , Humanos , Proteínas de Membrana/química , Proteínas de Membrana/genética , Proteínas de Membrana/imunologia , Microscopia Imunoeletrônica , Dados de Sequência Molecular , Proteínas Proteolipídicas Associadas a Linfócitos e Mielina , Oxirredução , Proteolipídeos/química , Homologia de Sequência de Aminoácidos
2.
Br J Haematol ; 112(1): 204-7, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11167804

RESUMO

Evidence is accumulating regarding CD95/CD95 ligand (Fas/FasL) pathway dysregulation in clonal diseases of the lymphohaemopoietic lineages. According to these observations, it has been proposed that this defect may represent one of the mechanisms of tumour progression. In large granular lymphocyte (LGL) leukaemia, dysregulated apoptosis may represent a key event in the development of malignancy and autoimmunity. This case report describes dysregulation of the Fas/FasL pathway in a chronic polyclonal expansion of CD3(+) LGLs associated with numerous serological immune abnormalities.


Assuntos
Complexo CD3 , Antígenos CD4 , Antígeno CD56 , Leucemia de Células T/imunologia , Linfócitos T/imunologia , Anticorpos Monoclonais/farmacologia , Apoptose , Autoimunidade , Southern Blotting , Estudos de Casos e Controles , Progressão da Doença , Proteína Ligante Fas , Feminino , Citometria de Fluxo , Células HL-60 , Humanos , Interleucina-2/farmacologia , Ativação Linfocitária , Glicoproteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Receptor fas/metabolismo
3.
Oncogene ; 19(32): 3647-55, 2000 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-10951571

RESUMO

Interleukin 3-dependent bone marrow and Ba/F3 cells present constitutive Fas expression. A dose dependent increase in Fas surface expression was induced in these cells by X-ray irradiation. Using primary cell cultures and established cell lines derived from p53-null mice (p53-/-), we demonstrated that the increase in Fas expression upon X-ray irradiation is dependent on the presence of at least one wild-type p53 allele. Fas induction by X-ray irradiation was negatively modulated by IL-3; an earlier Fas induction was observed in the absence of IL-3 or at low IL-3 concentrations. However, IL-3 withdrawal in non-irradiated cells did not induce an increase in Fas expression. X-ray irradiation of Ba/F3 cells induced the expression of functional Fas receptors. Therefore, in IL-3-dependent cells, IL-3 regulates the rate of Fas expression, which is correlated with the degree of apoptosis observed in X-irradiated cells. Finally, we demonstrate that IL-3 controls the degree of Fas expression induced by irradiation through a p53-mediated pathway.


Assuntos
Interleucina-3/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima/efeitos da radiação , Receptor fas/genética , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Células da Medula Óssea/efeitos da radiação , Membrana Celular/metabolismo , Células Cultivadas , Interleucina-3/genética , Interleucina-3/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fatores de Tempo , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/genética , Regulação para Cima/efeitos dos fármacos
4.
J Cell Biol ; 145(1): 141-51, 1999 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-10189374

RESUMO

The MAL (MAL/VIP17) proteolipid is a nonglycosylated integral membrane protein expressed in a restricted pattern of cell types, including T lymphocytes, myelin-forming cells, and polarized epithelial cells. Transport of the influenza virus hemagglutinin (HA) to the apical surface of epithelial Madin-Darby canine kidney (MDCK) cells appears to be mediated by a pathway involving glycolipid- and cholesterol- enriched membranes (GEMs). In MDCK cells, MAL has been proposed previously as being an element of the protein machinery for the GEM-dependent apical transport pathway. Using an antisense oligonucleotide-based strategy and a newly generated monoclonal antibody to canine MAL, herein we have approached the effect of MAL depletion on HA transport in MDCK cells. We have found that MAL depletion diminishes the presence of HA in GEMs, reduces the rate of HA transport to the cell surface, inhibits the delivery of HA to the apical surface, and produces partial missorting of HA to the basolateral membrane. These effects were corrected by ectopic expression of MAL in MDCK cells whose endogenous MAL protein was depleted. Our results indicate that MAL is necessary for both normal apical transport and accurate sorting of HA.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Proteínas de Membrana Transportadoras , Proteínas da Mielina , Proteolipídeos/fisiologia , Animais , Anticorpos Monoclonais/farmacologia , Transporte Biológico/efeitos dos fármacos , Polaridade Celular , Detergentes/farmacologia , Cães , Células Epiteliais/metabolismo , Rim , Lipídeos de Membrana/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Proteolipídicas Associadas a Linfócitos e Mielina , Oligonucleotídeos Antissenso/farmacologia , Proteolipídeos/antagonistas & inibidores , Proteolipídeos/genética , Proteolipídeos/imunologia , Ratos , Ratos Wistar , Transfecção
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