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2050-01-01
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THE FOUR TRYPANOSOMATID EIF4E HOMOLOGUES FALL INTO TWO SEPARATE GROUPS, WITH DISTINCT FEATURES IN PRIMARY SEQUENCE AND BIOLOGICAL PROPERTIES
Núcleo Celular / metabolismo
Proliferação celular
Sobrevivência Celular
Citoplasma / metabolismo
Fator de Iniciação Eucariotica-4E / química
Fator de Iniciação Eucariotica-4E / genética
Fator de Iniciação Eucariotica-4E / metabolismo
Regulamento de Expressão Gênica
Espaço intracelular / metabolismo
Dados de Sequencia Molecular
Ligação proteica
Transporte de Proteínas / fisiologia
Interferência de RNA
Alinhamento Sequencial
Trypanosoma / genética
Trypanosoma / metabolismo
Author
Affilliation
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
University of Cambridge. Department of Biochemistry. Cambridge, UK.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
University of Cambridge. Department of Biochemistry. Cambridge, UK.
University of Cambridge. Department of Biochemistry. Cambridge, UK.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
University of Cambridge. Department of Biochemistry. Cambridge, UK.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
University of Cambridge. Department of Biochemistry. Cambridge, UK.
University of Cambridge. Department of Biochemistry. Cambridge, UK.
Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Recife, PE, Brasil.
Abstract
Translation initiation in eukaryotes requires eIF4E, the cap binding protein, which mediates its function through an interaction with the scaffolding protein eIF4G, as part of the eIF4F complex. In trypanosomatids, four eIF4E homologues have been described but the specific function of each is not well characterized. Here, we report a study of these proteins in Trypanosoma brucei (TbEIF4E1 through 4). At the sequence level, they can be assigned to two groups: TbEIF4E1 and 2, similar in size to metazoan eIF4E1; and TbEIF4E3 and 4, with long N-terminal extensions. All are constitutively expressed, but whilst TbEIF4E1 and 2 localize to both the nucleus and cytoplasm, TbEIF4E3 and 4 are strictly cytoplasmic and are also more abundant. After knockdown through RNAi, TbEIF4E3 was the only homologue confirmed to be essential for viability of the insect procyclic form. In contrast, TbEIF4E1, 3 and 4 were all essential for the mammalian bloodstream form. Simultaneous RNAi knockdown of TbEIF4E1 and 2 caused cessation of growth and death in procyclics, but with a delayed impact on translation, whilst knockdown of TbEIF4E3 alone or a combined TbEIF4E1 and 4 knockdown led to substantial translation inhibition which preceded cellular death by several days, at least. Only TbEIF4E3 and 4 were found to interact with T. brucei eIF4G homologues; TbEIF4E3 bound both TbEIF4G3 and 4 whilst TbEIF4E4 bound only to TbEIF4G3. These results are consistent with TbEIF4E3 and 4 having distinct but relevant roles in initiation of protein synthesis.
DeCS
Sequência de AminoácidosNúcleo Celular / metabolismo
Proliferação celular
Sobrevivência Celular
Citoplasma / metabolismo
Fator de Iniciação Eucariotica-4E / química
Fator de Iniciação Eucariotica-4E / genética
Fator de Iniciação Eucariotica-4E / metabolismo
Regulamento de Expressão Gênica
Espaço intracelular / metabolismo
Dados de Sequencia Molecular
Ligação proteica
Transporte de Proteínas / fisiologia
Interferência de RNA
Alinhamento Sequencial
Trypanosoma / genética
Trypanosoma / metabolismo
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