Multiple elements in the eIF4G1 N-terminus promote assembly of eIF4G1â¢PABP mRNPs in vivo.
EMBO J
; 30(2): 302-16, 2011 Jan 19.
Article
em En
| MEDLINE
| ID: mdl-21139564
ABSTRACT
eIF4G is the scaffold subunit of the eIF4F complex, whose binding domains for eIF4E and poly(A)-binding protein (PABP) are thought to enhance formation of activated eIF4Fâ¢mRNAâ¢PABP complexes competent to recruit 43S pre-initiation complexes. We found that the RNA-binding region (RNA1) in the N-terminal domain (NTD) of yeast eIF4G1 can functionally substitute for the PABP-binding segment to rescue the function of an eIF4G1-459 mutant impaired for eIF4E binding. Assaying RNA-dependent PABP-eIF4G association in cell extracts suggests that RNA1, the PABP-binding domain, and two conserved elements (Box1 and Box2) between these segments have overlapping functions in forming native eIF4Gâ¢mRNAâ¢PABP complexes. In vitro experiments confirm the role of RNA1 in stabilizing eIF4G-mRNA association, and further indicate that RNA1 and Box1 promote PABP binding, in addition to RNA binding, by the eIF4G1 NTD. Our findings indicate that PABP-eIF4G association is only one of several interactions that stabilize eIF4Fâ¢mRNA complexes, and emphasize that closed-loop mRNP formation via PABP-eIF4G interaction is non-essential in vivo. Interestingly, two other RNA-binding regions in eIF4G1 have critical functions downstream of eIF4Fâ¢mRNA assembly.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ribonucleoproteínas
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Biossíntese de Proteínas
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Proteínas de Ligação a RNA
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Estrutura Terciária de Proteína
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Proteínas de Saccharomyces cerevisiae
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Proteínas de Ligação a Poli(A)
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Fator de Iniciação Eucariótico 4G
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Complexos Multiproteicos
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article