eIF5A facilitates translation termination globally and promotes the elongation of many non polyproline-specific tripeptide sequences

Abstract

AbstracteIF5A is an essential protein involved in protein synthesis, cell proliferation and animal development. High eIF5A expression is observed in many tumor types and has been linked to cancer metastasis. Recent studies have shown that eIF5A facilitates the translation elongation of stretches of consecutive prolines. Activated eIF5A binds to the empty E-site of stalled ribosomes, where it is thought to interact with the peptidyl-tRNA situated at the P-site. Here, we report a genome-wide analysis of ribosome stalling in Saccharomyces cerevisiae eIF5A depleted cells using 5Pseq. We confirm that, in the absence of eIF5A, ribosomes stall at proline stretches, and extend previous studies by identifying eIF5A-dependent ribosome pauses at termination and at >200 tripeptide motifs. We show that presence of proline, glycine and charged amino acids at the peptidyl transferase center and at the beginning of the peptide exit tunnel arrest ribosomes in eIF5A-depleted cells. Lack of eIF5A also renders ribosome accumulation at the stop codons. Our data indicate specific protein functional groups under the control of eIF5A, including ER-coupled translation and GTPases in yeast and cytoskeleton organization, collagen metabolism and cell differentiation in humans. Our results support a broad mRNA-specific role of eIF5A in translation and identify the conserved motifs that affect translation elongation from yeast to humans.

Transcriptome-wide sites of collided ribosomes reveal principles of translational pausing

“…Beyond the lack of proline, the specific amino acid and dipeptide motifs that we find enriched at the paused ribosomes ( Figure 3; Supplemental Table S2) show some resemblance as well as distinct differences to previous observations. For example, Asp and Glu have been associated with presumed pause sites (In-670 golia et al, 2011; Ibrahim et al, 2018), and Asp codons also figure among those whose footprint signal increases strongest (apart from Pro) in cells deficient of eIF5A (Pelechano and Alepuz, 2017;Schuller et al, 2017). The striking association of pause sites with isoleucine is an unexpected outcome of our study, as to our knowledge this amino acid is not typically reported among the top-listed 675 associations with paused ribosomes.…”

Polyamine metabolism regulates the T cell epigenome through hypusination

“…Based on this it is logical that changes in eIF5A function due to a failure of hypusination must be critical for the changes in CD4 + T cell function reported here. Functionally, eIF5A is a translation factor that when hypusinated preferentially regulates the translation of transcripts with specific sequence properties (Gutierrez et al, 2013;Pelechano and Alepuz, 2017;Schuller et al, 2017). What this subset of transcripts is in differentiating CD4 + T cells, and how their translation might impact the chromatin and transcriptional states of these cells, remains to be determined.…”

The polyproline‐motif of S6K2: eIF5A translational dependence and importance for protein‐protein interactions

“…Total protein extracts were analyzed by immunoblotting using anti-yeIF5A and anti-S6K2 antibodies. [15][16][17] In this context, a study in sensitive strains of S. cerevisiae demonstrated that eIF5A is essential for Bni1 translation. B, Band intensities of S6K2 protein produced at 10 and 12 hours after starting the experiment (3 and 5 hours after induction of the production by galactose, respectively) were quantified by densitometry.…”