Only a subset of the PAB1‐mRNP proteome is present in mRNA translation complexes

Zhang, Chongxu; Wang, Xin; Park, Shiwha; Chiang, Yueh Chin; Xi, Wen; Laue, Thomas M.; Denis, Clyde L.

doi:10.1002/pro.2490

Cited by 20 publications

(34 citation statements)

References 35 publications

(139 reference statements)

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“…A small portion of the protein also cosediments with the 80S and polysome fractions. These results are consistent with the observation that tagged Sbp1 was pulled down with 80S and polysomes (Zhang et al 2014;Wang et al 2016).…”

Section: A Mechanistic Model For Translation Regulation By Sbp1supporting

confidence: 92%

Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- and RGG-dependent manner

Brandariz-Núñez

Zeng

Lam

et al. 2017

RNA

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RNA-binding protein Sbp1 facilitates the decapping pathway in mRNA metabolism and inhibits global mRNA translation by an unclear mechanism. Here we report molecular interactions responsible for Sbp1-mediated translation inhibition of mRNA encoding the polyadenosine-binding protein (Pab1), an essential translation factor that stimulates mRNA translation and inhibits mRNA decapping in eukaryotic cells. We demonstrate that the two distal RRMs of Sbp1 bind to the poly(A) sequence in the 5 ′ ′ ′ ′ ′ UTR of the Pab1 mRNA specifically and cooperatively while the central RGG domain of the protein interacts directly with Pab1. Furthermore, methylation of arginines in the RGG domain abolishes the protein-protein interaction and the inhibitory effect of Sbp1 on translation initiation of Pab1 mRNA. Based on these results, the underlying mechanism for Sbp1-specific translational regulation is proposed. The functional differences of Sbp1 and RGG repeats alone on transcript-specific translation were observed, and a comparison of the results suggests the importance of remodeling the 5 ′ ′ ′ ′ ′ UTR by RNA-binding proteins in mRNA translation.

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Section: A Mechanistic Model For Translation Regulation By Sbp1supporting

confidence: 92%

Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- and RGG-dependent manner

Brandariz-Núñez

Zeng

Lam

et al. 2017

RNA

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“…Models for Sbp1p's function in translational repression suggest that the Sbp1 protein can directly bind mRNA and inhibit the function of translation initiation factors, or that the Sbp1 protein can directly bind mRNA and facilitate the full assembly of a translational repression complex. Sbp1 is presumed to bind the eIF4G translation initiation factor and carry out translational repression by this means (Rajyaguru et al, ; Zhang et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Chromosome VIII disomy influences the nonsense suppression efficiency and transition metal tolerance of the yeast Saccharomyces cerevisiae

Zadorsky

Sopova

Andreichuk

et al. 2015

Yeast

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The SUP35 gene of the yeast Saccharomyces cerevisiae encodes the translation termination factor eRF3. Mutations in this gene lead to the suppression of nonsense mutations and a number of other pleiotropic phenotypes, one of which is impaired chromosome segregation during cell division. Similar effects result from replacing the S. cerevisiae SUP35 gene with its orthologues. A number of genetic and epigenetic changes that occur in the sup35 background result in partial compensation for this suppressor effect. In this study we showed that in S. cerevisiae strains in which the SUP35 orthologue from the yeast Pichia methanolica replaces the S. cerevisiae SUP35 gene, chromosome VIII disomy results in decreased efficiency of nonsense suppression. This antisuppressor effect is not associated with decreased stop codon read-through. We identified SBP1, a gene that localizes to chromosome VIII, as a dosage-dependent antisuppressor that strongly contributes to the overall antisuppressor effect of chromosome VIII disomy. Disomy of chromosome VIII also leads to a change in the yeast strains' tolerance of a number of transition metal salts.

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“…The recent demonstration that analytical ultracentrifugation with fluorescent detection (AU-FDS) can rapidly and precisely identify sizes, components, and changes in composition of multiple protein complexes [ 11 , 12 ] indicates that AU-FDS can produce information presently either unavailable or difficult to obtain. We have consequently expanded the use of AU-FDS to determine the absolute abundances of proteins within protein synthesis complexes using the translating ribosome as our model system.…”

Section: Introductionmentioning

confidence: 99%

“…The basic technique utilizes our previous AU-FDS identification of the translating ribosomes following a one-step affinity purification step using a Flag-tagged component of the protein synthesis machinery. These complexes consist of 40S and 60S ribosomal subunits, the translational initiation factors eIF4E, eIF4G, and PAB1 [ 11 ] and at least five other proteins: eRF1 (translation termination), SBP1 (translational repression) [ 13 ], and the general mRNA binding proteins SLF1, SSD1, and PUB1 [ 12 ]. AU-FDS combined with the one-step purification of translating complexes also specifically offers an opportunity to study the 77S monosomal translating complex.…”

Section: Introductionmentioning

confidence: 99%

Stoichiometry and Change of the mRNA Closed-Loop Factors as Translating Ribosomes Transit from Initiation to Elongation

Wang

Toomey

et al. 2016

PLoS ONE

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Protein synthesis is a highly efficient process and is under exacting control. Yet, the actual abundance of translation factors present in translating complexes and how these abundances change during the transit of a ribosome across an mRNA remains unknown. Using analytical ultracentrifugation with fluorescent detection we have determined the stoichiometry of the closed-loop translation factors for translating ribosomes. A variety of pools of translating polysomes and monosomes were identified, each containing different abundances of the closed-loop factors eIF4E, eIF4G, and PAB1 and that of the translational repressor, SBP1. We establish that closed-loop factors eIF4E/eIF4G dissociated both as ribosomes transited polyadenylated mRNA from initiation to elongation and as translation changed from the polysomal to monosomal state prior to cessation of translation. eIF4G was found to particularly dissociate from polyadenylated mRNA as polysomes moved to the monosomal state, suggesting an active role for translational repressors in this process. Consistent with this suggestion, translating complexes generally did not simultaneously contain eIF4E/eIF4G and SBP1, implying mutual exclusivity in such complexes. For substantially deadenylated mRNA, however, a second type of closed-loop structure was identified that contained just eIF4E and eIF4G. More than one eIF4G molecule per polysome appeared to be present in these complexes, supporting the importance of eIF4G interactions with the mRNA independent of PAB1. These latter closed-loop structures, which were particularly stable in polysomes, may be playing specific roles in both normal and disease states for specific mRNA that are deadenylated and/or lacking PAB1. These analyses establish a dynamic snapshot of molecular abundance changes during ribosomal transit across an mRNA in what are likely to be critical targets of regulation.

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Only a subset of the PAB1‐mRNP proteome is present in mRNA translation complexes

Cited by 20 publications

References 35 publications

Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- and RGG-dependent manner

Sbp1 modulates the translation of Pab1 mRNA in a poly(A)- and RGG-dependent manner

Chromosome VIII disomy influences the nonsense suppression efficiency and transition metal tolerance of the yeast Saccharomyces cerevisiae

Stoichiometry and Change of the mRNA Closed-Loop Factors as Translating Ribosomes Transit from Initiation to Elongation

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