Dynamic cycling of eIF2 through a large eIF2B-containing cytoplasmic body: implications for translation control.
J Cell Biol
; 170(6): 925-34, 2005 Sep 12.
Article
em En
| MEDLINE
| ID: mdl-16157703
ABSTRACT
The eukaryotic translation initiation factor 2B (eIF2B) provides a fundamental controlled point in the pathway of protein synthesis. eIF2B is the heteropentameric guanine nucleotide exchange factor that converts eIF2, from an inactive guanosine diphosphate-bound complex to eIF2-guanosine triphosphate. This reaction is controlled in response to a variety of cellular stresses to allow the rapid reprogramming of cellular gene expression. Here we demonstrate that in contrast to other translation initiation factors, eIF2B and eIF2 colocalize to a specific cytoplasmic locus. The dynamic nature of this locus is revealed through fluorescence recovery after photobleaching analysis. Indeed eIF2 shuttles into these foci whereas eIF2B remains largely resident. Three different strategies to decrease the guanine nucleotide exchange function of eIF2B all inhibit eIF2 shuttling into the foci. These results implicate a defined cytoplasmic center of eIF2B in the exchange of guanine nucleotides on the eIF2 translation initiation factor. A focused core of eIF2B guanine nucleotide exchange might allow either greater activity or control of this elementary conserved step in the translation pathway.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Biossíntese de Proteínas
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Fator de Iniciação 2 em Eucariotos
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Corpos de Inclusão
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Fator de Iniciação 2B em Eucariotos
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Proteínas de Saccharomyces cerevisiae
Idioma:
En
Revista:
J Cell Biol
Ano de publicação:
2005
Tipo de documento:
Article