Properties of the ternary complex formed by yeast eIF4E, p20 and mRNA.
Sci Rep
; 8(1): 6707, 2018 04 30.
Article
em En
| MEDLINE
| ID: mdl-29712996
ABSTRACT
Yeast p20 is a small, acidic protein that binds eIF4E, the cap-binding protein. It has been proposed to affect mRNA translation and degradation, however p20's function as an eIF4E-binding protein (4E-BP) and its physiological significance has not been clearly established. In this paper we present data demonstrating that p20 is capable of binding directly to mRNA due to electrostatic interaction of a stretch of arginine and histidine residues in the protein with negatively charged phosphates in the mRNA backbone. This interaction contributes to formation of a ternary eIF4E/p20/capped mRNA complex that is more stable than complexes composed of capped mRNA bound to eIF4E in the absence of p20. eIF4E/p20 complex was found to have a more pronounced stimulatory effect on capped mRNA translation than purified eIF4E alone. Addition of peptides containing the eIF4E-binding domains present in p20 (motif âYTIDELF), in eIF4G (motif âYGPTFLL) or Eap1 (motif âYSMNELY) completely inhibited eIF4E-dependent capped mRNA translation (in vitro), but had a greatly reduced inhibitory effect when eIF4E/p20 complex was present. We propose that the eIF4E/p20/mRNA complex serves as a stable depository of mRNAs existing in a dynamic equilibrium with other complexes such as eIF4E/eIF4G (required for translation) and eIF4E/Eap1 (required for mRNA degradation).
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Base de dados:
MEDLINE
Assunto principal:
RNA Mensageiro
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Proteínas de Saccharomyces cerevisiae
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Fator de Iniciação 4E em Eucariotos
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Complexo Proteico Nuclear de Ligação ao Cap
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Fatores de Complexo Ternário
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article