The Yeast Eukaryotic Initiation Factor 4G (eIF4G) HEAT Domain Interacts with eIF1 and eIF5 and Is Involved in Stringent AUG Selection
| Autor: | Tobias von der Haar, C. Ranjit Singh, Miki, Bin Li, Alan G. Hinnebusch, John E.G. McCarthy, Hui He, Katsura Asano |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Recombinant Fusion Proteins
viruses Mutant Gene Expression Saccharomyces cerevisiae Biology Binding Competitive Models Biological environment and public health chemistry.chemical_compound Eukaryotic initiation factor Point Mutation Eukaryotic Initiation Factors Codon Molecular Biology Glutathione Transferase EIF4G EIF4E Temperature food and beverages Cell Biology Precipitin Tests Molecular biology Protein Structure Tertiary Cell biology Kinetics EIF1 Phenotype chemistry Protein Biosynthesis eIF4A Mutation Transcription preinitiation complex Eukaryotic Initiation Factor-4G Ribosomes Gene Deletion Plasmids Protein Binding Binding domain |
| Zdroj: | Molecular and Cellular Biology. 23:5431-5445 |
| ISSN: | 1098-5549 0270-7306 |
| DOI: | 10.1128/mcb.23.15.5431-5445.2003 |
| Popis: | Eukaryotic initiation factor 4G (eIF4G) promotes mRNA recruitment to the ribosome by binding to the mRNA cap- and poly(A) tail-binding proteins eIF4E and Pap1p. eIF4G also binds eIF4A at a distinct HEAT domain composed of five stacks of antiparallel alpha-helices. The role of eIF4G in the later steps of initiation, such as scanning and AUG recognition, has not been defined. Here we show that the entire HEAT domain and flanking residues of Saccharomyces cerevisiae eIF4G2 are required for the optimal interaction with the AUG recognition factors eIF5 and eIF1. eIF1 binds simultaneously to eIF4G and eIF3c in vitro, as shown previously for the C-terminal domain of eIF5. In vivo, co-overexpression of eIF1 or eIF5 reverses the genetic suppression of an eIF4G HEAT domain Ts(-) mutation by eIF4A overexpression. In addition, excess eIF1 inhibits growth of a second eIF4G mutant defective in eIF4E binding, which was also reversed by co-overexpression of eIF4A. Interestingly, excess eIF1 carrying the sui1-1 mutation, known to relax the accuracy of start site selection, did not inhibit the growth of the eIF4G mutant, and sui1-1 reduced the interaction between eIF4G and eIF1 in vitro. Moreover, a HEAT domain mutation altering eIF4G moderately enhances translation from a non-AUG codon. These results strongly suggest that the binding of the eIF4G HEAT domain to eIF1 and eIF5 is important for maintaining the integrity of the scanning ribosomal preinitiation complex. |
| Databáze: | OpenAIRE |
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