Translatomic analysis of the wild-type (WT) and total body eIF2A-KO mouse liver tissue
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE334597 | GEO | 2026/09/16
REPOSITORIES: GEO
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Project description:Earlier investigations have associated mammalian eIF2A with Met-tRNAi binding to the 40S subunit and its recruitment to specialized mRNAs in a GTP-independent manner. Additionally, eIF2A has been implicated in non-AUG start codon initiation, particularly under conditions where eIF2 function is attenuated by phosphorylation of its α-subunit during stress or starvation. However, the precise role of eIF2A in vivo translation remains unclear. Moreover, it's uncertain if the conserved ortholog in budding yeast can functionally substitute for eIF2 during stress. To address these questions, we conducted ribosome profiling on a yeast deletion mutant lacking eIF2A, alongside isogenic wild-type (WT) cells, both in the presence or absence of eIF2α phosphorylation induced by amino acid starvation.
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Project description:The RNA-binding protein eIF2A has been implicated in a variety of cellular processes including tumorigenesis. This role has been attributed to its function as alternative translation initiation factor. However, the mechanisms by which eIF2A regulates translation and its contribution to oncogenic transformation are unclear. Here, we shed light on these aspects using a melanoma cell model consisting of the non-tumoral melanocytic cell line MelST and its metastatic counterpart obtained by RasV12 overexpression (MelSTR). Depletion of eIF2A from MelST and MelSTR cells revealed acquired dependencies upon Ras transformation for migration. Surprisingly, analysis of the transcriptome (RNA-Seq) and translatome (ribosome profiling) upon eIF2A depletion showed minor to no changes in translation. RIP-Seq and RT-qPCR furthermore indicate that eIF2A binds mRNA targets in a translation-independent manner. Interestingly, protein interactome analyses point towards a function of eIF2A in cytoskeletal remodeling and indeed we can show that eIF2A localizes to the centrosome and affects its composition and orientation, linking eIF2A with migration. In addition, eIF2A promotes migration in a manner that depends on its RNA-binding activity. Together, these results indicate that eIF2A does not function as a translation factor in melanoma cells, but through a novel function which is based on its RNA-binding activity and its connections to the centrosome.
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Project description:The RNA-binding protein eIF2A has been implicated in a variety of cellular processes including tumorigenesis. This role has been attributed to its function as alternative translation initiation factor. However, the mechanisms by which eIF2A regulates translation and its contribution to oncogenic transformation are unclear. Here, we shed light on these aspects using a melanoma cell model consisting of the non-tumoral melanocytic cell line MelST and its metastatic counterpart obtained by RasV12 overexpression (MelSTR). Depletion of eIF2A from MelST and MelSTR cells revealed acquired dependencies upon Ras transformation for migration. Surprisingly, analysis of the transcriptome (RNA-Seq) and translatome (ribosome profiling) upon eIF2A depletion showed minor to no changes in translation. RIP-Seq and RT-qPCR furthermore indicate that eIF2A binds mRNA targets in a translation-independent manner. Interestingly, protein interactome analyses point towards a function of eIF2A in cytoskeletal remodeling and indeed we can show that eIF2A localizes to the centrosome and affects its composition and orientation, linking eIF2A with migration. In addition, eIF2A promotes migration in a manner that depends on its RNA-binding activity. Together, these results indicate that eIF2A does not function as a translation factor in melanoma cells, but through a novel function which is based on its RNA-binding activity and its connections to the centrosome.
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Project description:The RNA-binding protein eIF2A has been implicated in a variety of cellular processes including tumorigenesis. This role has been attributed to its function as alternative translation initiation factor. However, the mechanisms by which eIF2A regulates translation and its contribution to oncogenic transformation are unclear. Here, we shed light on these aspects using a melanoma cell model consisting of the non-tumoral melanocytic cell line MelST and its metastatic counterpart obtained by RasV12 overexpression (MelSTR). Depletion of eIF2A from MelST and MelSTR cells revealed acquired dependencies upon Ras transformation for migration. Surprisingly, analysis of the transcriptome (RNA-Seq) and translatome (ribosome profiling) upon eIF2A depletion showed minor to no changes in translation. RIP-Seq and RT-qPCR furthermore indicate that eIF2A binds mRNA targets in a translation-independent manner. Interestingly, protein interactome analyses point towards a function of eIF2A in cytoskeletal remodeling and indeed we can show that eIF2A localizes to the centrosome and affects its composition and orientation, linking eIF2A with migration. In addition, eIF2A promotes migration in a manner that depends on its RNA-binding activity. Together, these results indicate that eIF2A does not function as a translation factor in melanoma cells, but through a novel function which is based on its RNA-binding activity and its connections to the centrosome.
2025-08-05 | PXD055625 | Pride
Project description:Many positive-strand RNA viruses, including all known coronaviruses, employ programmed –1 ribosomal frameshifting (–1 PRF) to regulate the translation of polycistronic viral RNAs. However, only a few host factors have been shown to regulate –1 PRF. Through a reporter-based genome-wide CRISPR/Cas9 knockout screen, we identified several host factors that either suppressed or enhanced –1 PRF of SARS-CoV-2. One of these factors is eukaryotic translation initiation factor 2A (eIF2A), which specifically and directly enhanced –1 PRF in vitro and in cells. Consistent with the crucial role of efficient –1 PRF in transcriptase/replicase expression, loss of eIF2A reduced SARS-CoV-2 replication in cells. Transcriptome-wide analysis of eIF2A-interacting RNAs showed that eIF2A primarily interacted with 18S ribosomal RNA near the contacts between the SARS-CoV-2 frameshift-stimulatory element (FSE) and the ribosome. Thus, our results revealed an unexpected role for eIF2A in modulating the translation of specific RNAs independent of its previously described role during initiation.
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Project description:Various cellular stresses lead to an inhibition of steady-state translation driven by the cytoplasmic cap-binding protein eIF4E via the integrated stress response (ISR) in order to mitigate stress-induced damage. A caveat is that essential proteins for cell survival or maintenance should be expressed even under ISR-activated conditions. Here, we find that when global translation is compromised due to eIF2α phosphorylation during ISR, eIF2A takes over the function of eIF2α for Met-tRNAi delivery. Notably, preferential association between eIF2A and cellular factors involved in the pioneer round of translation driven by nuclear cap-binding protein complex (CBP20/80) allows the pioneer translation to occur during ISR. We also observe that ISR is activated in growing human embryonic stem cell (hESC) colonies. Under these naturally arising ISR conditions, eIF2A-mediated pioneer translation is active and safeguards self-renewal and differentiation of hESCs. Collectively, we unravel the molecular mechanism underlying translation that secures protein synthesis under cellular stress.
2026-03-30 | GSE225009 | GEO
Project description:Various cellular stresses lead to an inhibition of steady-state translation driven by the cytoplasmic cap-binding protein eIF4E via the integrated stress response (ISR) in order to mitigate stress-induced damage. A caveat is that essential proteins for cell survival or maintenance should be expressed even under ISR-activated conditions. Here, we find that when global translation is compromised due to eIF2α phosphorylation during ISR, eIF2A takes over the function of eIF2α for Met-tRNAi delivery. Notably, preferential association between eIF2A and cellular factors involved in the pioneer round of translation driven by nuclear cap-binding protein complex (CBP20/80) allows the pioneer translation to occur during ISR. We also observe that ISR is activated in growing human embryonic stem cell (hESC) colonies. Under these naturally arising ISR conditions, eIF2A-mediated pioneer translation is active and safeguards self-renewal and differentiation of hESCs. Collectively, we unravel the molecular mechanism underlying translation that secures protein synthesis under cellular stress.
2026-03-30 | GSE225010 | GEO
Project description:Translation initiation is a complex and highly regulated process that represents an important mechanism, controlling gene expression. eIF2A was proposed as an alternative initiation factor, however, its role and biological targets remain to be discovered. To further gain insight into the function of eIF2A in Saccharomyces cerevisiae, we identified mRNAs associated with the eIF2A complex and showed that 24% of the most enriched mRNAs encode proteins related to cell wall biogenesis and maintenance. In agreement with this result, we showed that an eIF2A deletion sensitized cells to cell wall damage induced by calcofluor white. eIF2A overexpression led to a growth defect, correlated with decreased synthesis of several cell wall proteins. In contrast, no changes were observed in the transcriptome, suggesting that eIF2A controls the expression of cell wall-related proteins at a translational level. The biochemical characterization of the eIF2A complex revealed that it strongly interacts with the RNA binding protein, Ssd1, which is a negative translational regulator, controlling the expression of cell wall-related genes. Interestingly, eIF2A and Ssd1 bind several common mRNA targets and we found that the binding of eIF2A to some targets was mediated by Ssd1. Surprisingly, we further showed that eIF2A is physically and functionally associated with the exonuclease Xrn1 and other mRNA degradation factors, suggesting an additional level of regulation. Altogether, our results highlight new aspects of this complex and redundant fine-tuned regulation of proteins expression related to the cell wall, a structure required to maintain cell shape and rigidity, providing protection against harmful environmental stress.
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