Human Eukaryotic Initiation Factor 4G (eIF4G) Protein Binds to eIF3c, -d, and -e to Promote mRNA Recruitment to the Ribosome

Villa, Nancy Y.; Do, Angelie; Hershey, John W.B.; Fraser, Christopher S.

doi:10.1074/jbc.m113.517011

Cited by 137 publications

(182 citation statements)

References 47 publications

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“…16,19,25 Although eIF4A binds the HEAT-1 and HEAT-2 domains of plant eIFiso4G and eIF4G, they differ in that the eIFiso4G HEAT-1 domain is sufficient to bind eIF4A whereas a short region immediately C-proximal to the HEAT-1 domain of eIF4G is needed in addition to the HEAT-1 domain, 12,13 consistent with observations made with animal eIF4G in which the HEAT-1 domain alone bound eIF4A with lower affinity than did a longer region of eIF4G. 26 In animal eIF4G, eIF3 binds to a 90 amino acid region just Cproximal to the HEAT-1 domain through its c, d, and e subunits 27,28 which was reported to bind in a cooperative manner with eIF4A 29 although this was not confirmed in a subsequent study. 28 Whether eIF3 binds to the corresponding region in plant eIF4G or eIFiso4G remains to be determined.…”

Section: Plants Express a Novel Eif4g Isoform Not Found In Other Eukasupporting

confidence: 74%

“…26 In animal eIF4G, eIF3 binds to a 90 amino acid region just Cproximal to the HEAT-1 domain through its c, d, and e subunits 27,28 which was reported to bind in a cooperative manner with eIF4A 29 although this was not confirmed in a subsequent study. 28 Whether eIF3 binds to the corresponding region in plant eIF4G or eIFiso4G remains to be determined. eIF1 and eIF5 bind yeast eIF4G within an arginine and serine rich domain that lies just N-proximal to the HEAT-1 domain and their interaction with eIF4G is competitive.…”

Section: Plants Express a Novel Eif4g Isoform Not Found In Other Eukamentioning

confidence: 85%

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The Role of the Poly(A) binding protein in the assembly of the Cap-binding complex during translation initiation in plants

Gallie¹

2014

translation

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Translation initiation in eukaryotes requires the involvement of multiple initiation factors (eIFs) that facilitate the binding of the 40 S ribosomal subunit to an mRNA and assemble the 80 S ribosome at the correct initiation codon. eIF4F, composed of eIF4E, eIF4A, and eIF4G, binds to the 5 0 -cap structure of an mRNA and prepares an mRNA for recruitment of a 40 S subunit. eIF4B promotes the ATPdependent RNA helicase activity of eIF4A and eIF4F needed to unwind secondary structure present in a 5 0 -leader that would otherwise impede scanning of the 40 S subunit during initiation. The poly(A) binding protein (PABP), which binds the poly(A) tail, interacts with eIF4G and eIF4B to promote circularization of an mRNA and stimulates translation by promoting 40 S subunit recruitment. Thus, these factors serve essential functions in the early steps of protein synthesis. Their assembly and function requires multiple interactions that are competitive in nature and determine the nature of interactions between the termini of an mRNA. In this review, the domain organization and partner protein interactions are presented for the factors in plants which share similarities with those in animals and yeast but differ in several important respects. The functional consequences of their interactions on factor activity are also discussed.

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Section: Plants Express a Novel Eif4g Isoform Not Found In Other Eukasupporting

confidence: 74%

Section: Plants Express a Novel Eif4g Isoform Not Found In Other Eukamentioning

confidence: 85%

The Role of the Poly(A) binding protein in the assembly of the Cap-binding complex during translation initiation in plants

Gallie¹

2014

translation

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“…eIF4A binds to both of these domains, whereas PABP binds within the HEAT-1 domain (15). eIF4B binds adjacent to this domain to a region also implicated in interaction with eIF3 in animal eIF4G (15,28,29). Analysis of those residues in eIFiso4G2, which differ from eIFiso4G1 isoforms but are conserved in eIFiso4G2 isoforms revealed a relatively small number of residues that are eIFiso4G2-specific (residues with asterisks in Fig.…”

Section: Loss Of An Eif4g Isoform Affects Transcript Abundance-the Lumentioning

confidence: 99%

“…It should be noted that eIF3 binds to the corresponding region in animal eIF4G but not in yeast eIF4G (29,33,34) and as such, it would be necessary to determine which is the case for plant eIFiso4G isoforms to consider whether the observed eIFiso4G2-specific sequence changes might affect this interaction. The eIFiso4G2-specific differences are clustered together in the central region of the eIF4B interaction domain and ERVRFSREEILQHR…”

Section: --Gimkmp----mddggweiqrtrsmprgnrqtvqqpgarvqpppafnksvsvnsrllpqmentioning

confidence: 99%

Eukaryotic Initiation Factor eIFiso4G1 and eIFiso4G2 Are Isoforms Exhibiting Distinct Functional Differences in Supporting Translation in Arabidopsis

Gallie

2016

Journal of Biological Chemistry

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The eukaryotic translation initiation factor (eIF) 4G is required during protein synthesis to promote the assembly of several factors involved in the recruitment of a 40S ribosomal subunit to an mRNA. Although many eukaryotes express two eIF4G isoforms that are highly similar, the eIF4G isoforms in plants, referred to as eIF4G and eIFiso4G, are highly divergent in size, sequence, and domain organization but both can interact with eIF4A, eIF4B, eIF4E isoforms, and the poly(A)-binding protein.Nevertheless, eIF4G and eIFiso4G from wheat exhibit preferences in the mRNAs they translate optimally. For example, mRNA containing the 5-leader (called ⍀) of tobacco mosaic virus preferentially uses eIF4G in wheat germ lysate. In this study, the eIF4G isoform specificity of ⍀ was used to examine functional differences of the eIF4G isoforms in Arabidopsis. As in wheat, ⍀-mediated translation was reduced in an eif4g null mutant. Loss of the eIFiso4G1 isoform, which is similar in sequence to wheat eIFiso4G, did not substantially affect ⍀-mediated translation. However, loss of the eIFiso4G2 isoform substantially reduced ⍀-mediated translation. eIFiso4G2 is substantially divergent from eIFiso4G1 and is present only in the Brassicaceae, suggesting a recent evolution. eIFiso4G2 isoforms exhibit sequence-specific differences in regions representing partner protein and RNA binding sites. Loss of any eIF4G isoform also resulted in a substantial reduction in reporter transcript level. These results suggest that eIFiso4G2 appeared late in plant evolution and exhibits more functional similarity with eIF4G than with eIFiso4G1 during ⍀-mediated translation.The synthesis of proteins from cellular mRNAs requires several translation initiation factors that assist in recruiting the 40S ribosomal subunit to an mRNA as well as in the recognition of the initiation codon and in the assembly of the 80S ribosome (1-3). Eukaryotic initiation factor (eIF) 4F is essential to promote 40S subunit binding to an mRNA and to assist in 40S subunit scanning of the 5Ј-leader in search of the initiation codon. eIF4F is a multisubunit factor composed of eIF4E, which binds the 5Ј-cap structure; the RNA helicase, eIF4A, which unwinds the secondary structure in a 5Ј-leader that would otherwise inhibit 40S subunit scanning; and the scaffolding protein, eIF4G, which interacts with eIF4E, eIF4A, eIF4B (which stimulates the RNA helicase activity of eIF4A), eIF3 (required for 40 S binding to an mRNA), and the poly(A)-binding protein (PABP) 2 (2, 4 -6). The interactions between eIF4G and eIF4E and between eIF4G and PABP results in mRNA circularization that stimulates translation by promoting 40S subunit recruitment (7,8). An interaction between eIF4B and PABP further increases the affinity for poly(A) RNA of PABP (9 -11). These factors, therefore, are necessary for the efficient translation of most mRNAs.Although plants express two forms of eIF4G as do many eukaryotes (12), the plant isoforms are more divergent from each other than observed between eIF4G isoforms in othe...

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“…The 43S PIC is directed to bind an mRNA at the 59 end. In mammalian cells, eIF4G binds the 43S complex via contacts with the c, d, and e subunits of eIF3 (Korneeva et al 2000;LeFebvre et al 2006;Villa et al 2013). Neither eIF3d, eIF3e, nor the eIF4G domain used by mammals is conserved in yeast.…”

Section: Mrna Recruitment Of the 43s Picmentioning

confidence: 99%

Mechanism and Regulation of Protein Synthesis in Saccharomyces cerevisiae

2016

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In this review, we provide an overview of protein synthesis in the yeast Saccharomyces cerevisiae. The mechanism of protein synthesis is well conserved between yeast and other eukaryotes, and molecular genetic studies in budding yeast have provided critical insights into the fundamental process of translation as well as its regulation. The review focuses on the initiation and elongation phases of protein synthesis with descriptions of the roles of translation initiation and elongation factors that assist the ribosome in binding the messenger RNA (mRNA), selecting the start codon, and synthesizing the polypeptide. We also examine mechanisms of translational control highlighting the mRNA cap-binding proteins and the regulation of GCN4 and CPA1 mRNAs.

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Human Eukaryotic Initiation Factor 4G (eIF4G) Protein Binds to eIF3c, -d, and -e to Promote mRNA Recruitment to the Ribosome

Cited by 137 publications

References 47 publications

The Role of the Poly(A) binding protein in the assembly of the Cap-binding complex during translation initiation in plants

The Role of the Poly(A) binding protein in the assembly of the Cap-binding complex during translation initiation in plants

Eukaryotic Initiation Factor eIFiso4G1 and eIFiso4G2 Are Isoforms Exhibiting Distinct Functional Differences in Supporting Translation in Arabidopsis

Mechanism and Regulation of Protein Synthesis in Saccharomyces cerevisiae

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