Translational control of skeletal muscle mass by the transcriptional repressor BCL6
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE190956 | GEO | 2023/12/26
REPOSITORIES: GEO
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Project description:Eukaryotic translation initiation factor 4E (eIF4E)–binding protein 1 (4E-BP1) inhibits cap-dependent translation in eukaryotes by competing with eIF4G for an interaction with eIF4E. Phos-phorylation at Ser-83 of 4E-BP1 occurs during mitosis through the activity of cyclin-dependent kinase 1 (CDK1)/cyclin B rather than through canonical mTOR kinase activity. Here, we investi-gated the interaction of eIF4E with 4E-BP1 or eIF4G during interphase and mitosis. We observed that 4E-BP1 and eIF4G bind eIF4E at similar levels during interphase and mitosis. The most highly phosphorylated mitotic 4E-BP1 isoform (δ) did not interact with eIF4E, whereas a distinct 4E-BP1 phospho-isoform, EB-γ—phosphorylated at Thr-70, Ser-83, and Ser-101—bound to eIF4E during mitosis. Two-dimensional gel electropho-retic analysis corroborated the identity of the phosphorylation marks on the eIF4E-bound 4E-BP1 isoforms and uncovered a population of phosphorylated 4E-BP1 molecules lacking Thr-37/Thr-46–priming phosphorylation. Moreover, proximity ligation assays for phospho–4E-BP1 and eIF4E revealed different in situ interactions during interphase and mitosis. The eIF4E:eIF4G interaction was not inhibited, but rather increased in mitotic cells, consistent with active translation initiation during mitosis. Phospho-defective substitution of 4E-BP1 at Ser-83 did not change global translation or individual mRNA translation profiles as measured by single-cell nascent protein synthesis and eIF4G RNA-immunoprecipitation sequencing. Mitotic 5’-terminal oligopyrimidine RNA translation was active and, unlike interphase translation, resistant to mTOR inhibition. Our findings reveal the phosphorylation profiles of 4E-BP1 isoforms and their interactions with eIF4E throughout the cell cycle and indicate that 4E-BP1 does not specifically inhibit translation initiation during mitosis.
2019-06-14 | GSE131668 | GEO
Project description:Activation of the mechanistic target of rapamycin complex 1 (mTORC1) contributes to the development of chronic pain. However, the specific mechanisms by which mTORC1 causes hypersensitivity remain elusive. The eukaryotic initiation factor 4E-binding protein 1 (4E-BP1) is a key mTORC1 downstream effector that represses translation initiation. Here we show that nociceptor-specific deletion of 4E-BP1, mimicking activation of mTORC1-dependent translation, is sufficient to cause mechanical hypersensitivity.
2023-03-27 | GSE227978 | GEO
Project description:Mitosis-related phosphorylation of the eukaryotic translation suppressor 4E-BP1 and its interaction with eukaryotic translation initiation factor 4E (eIF4E)
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Project description:The eukaryotic elongation factor-2 kinase, eEF2K, restricts protein translation elongation, and was identified as a potential therapeutic target for diverse types of cancers including triple negative breast cancer (TNBC; PMID: 25330770). We have recently found that inhibition of eEF2K synergizes with depletion of eukaryotic translation initiation factor 4E-binding protein 1 (eIF4EBP1; 4E-BP1), a suppressor of eukaryotic protein translation initiation factor 4E (eIF4E), leading to effective growth suppression of TNBC cells in culture. We performed LC-MS/MS analysis following depletion of eEF2K and/or 4EBP in a TNBC cell line, Hs578t (YoungJun Ju & Eldad Zacksenhaus, manuscript in revisions). Depletion of these factors had overlapping effects on the proteome with the highest impact on Collagen containing extracellular matrix (e.g. COL1A1). The complete LC-MS/MS data sets (control vehicle; eEF2K-depletion, 4EBP1-depletion; combined eEF2k plus 4EBP1-depletion) are provided herein.
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Project description:Spinal microglia play a pivotal role in the development of neuropathic pain. Peripheral nerve injury induces changes in the transcriptional profile of microglia, including increased expression of components of translational machinery. Whether microglial protein synthesis is stimulated following nerve injury and has a functional role in mediating pain hypersensitivity is unknown. Here, we show that nascent protein synthesis is upregulated in spinal microglia following peripheral nerve injury. Stimulating mRNA translation in microglia, via selective ablation of the translational repressor, eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), promoted the transition of microglia to a reactive state and induced mechanical hypersensitivity. Conversely, inhibiting microglial translation by expressing mutant 4E-BP1 in microglia attenuated their peripheral nerve injury-induced activation and alleviated neuropathic pain. Thus, the stimulation of 4E-BP1-dependent translation promotes microglia reactivity and mechanical hypersensitivity, whereas its inhibition alleviates neuropathic pain.
2024-01-31 | GSE254472 | GEO
Project description:Aggressive double and triple hit (DH/TH) DLBCL feature activation of Hsp90 stress pathways. Herein, we show that Hsp90 controls post-transcriptional dynamics of key mRNA species including those encoding BCL6, MYC and BCL2. Using a proteomics approach, we found that Hsp90 binds to and maintains activity of eIF4E (eukaryotic translation initiation factor 4E). EIF4E drives nuclear export and translation of BCL6, MYC and BCL2 mRNA. eIF4E RIP-sequencing in DLBCL suggests that nuclear eIF4E controls an extended program that includes BCR signaling, cellular metabolism and epigenetic regulation. Accordingly, eIF4E was required for survival of DLBCL including the most aggressive subtypes DH/TH lymphomas. Indeed, eIF4E inhibition induces tumor regression in cell line and patient-derived tumorgrafts of TH-DLBCL, even in the presence of elevated Hsp90 activity. Targeting Hsp90 is typically limited by counter-regulatory elevation of Hsp70B, which induces resistance to Hsp90 inhibitors. Surprisingly, we identify Hsp70 mRNA as an eIF4E target. In this way, eIF4E inhibition can overcome drug resistance to Hsp90 inhibitors. Accordingly, rational combinatorial inhibition of eIF4E and Hsp90 inhibitors resulted in cooperative anti-lymphoma activity in DH/TH DLBCL in vitro and in vivo.
2016-01-11 | GSE63265 | GEO
Project description:Aggressive double and triple hit (DH/TH) DLBCL feature activation of Hsp90 stress pathways. Herein, we show that Hsp90 controls post-transcriptional dynamics of key mRNA species including those encoding BCL6, MYC and BCL2. Using a proteomics approach, we found that Hsp90 binds to and maintains activity of eIF4E (eukaryotic translation initiation factor 4E). EIF4E drives nuclear export and translation of BCL6, MYC and BCL2 mRNA. eIF4E RIP-sequencing in DLBCL suggests that nuclear eIF4E controls an extended program that includes BCR signaling, cellular metabolism and epigenetic regulation. Accordingly, eIF4E was required for survival of DLBCL including the most aggressive subtypes DH/TH lymphomas. Indeed, eIF4E inhibition induces tumor regression in cell line and patient-derived tumorgrafts of TH-DLBCL, even in the presence of elevated Hsp90 activity. Targeting Hsp90 is typically limited by counter-regulatory elevation of Hsp70B, which induces resistance to Hsp90 inhibitors. Surprisingly, we identify Hsp70 mRNA as an eIF4E target. In this way, eIF4E inhibition can overcome drug resistance to Hsp90 inhibitors. Accordingly, rational combinatorial inhibition of eIF4E and Hsp90 inhibitors resulted in cooperative anti-lymphoma activity in DH/TH DLBCL in vitro and in vivo. We found that eIF4E activity regulates the nuclear export of BCL6, MYC, and BCL2 in DH/TH DLBCLs. To determine the extent of nuclear eIF4E activity in DH/TH DLBCLs and how these programs can support the oncogenic activity of BCL6, MYC and/or BCL2 transcripts, we conducted eIF4E-RIP of nuclear RNA followed by RNA-sequencing in OCI-Ly1 cells in triplicates. To understand the changes in gene expression after ribavarin in a clinically relevant sample, we generated a patient-derived xenograft (PDX) in NSG mice from a de-identified specimen isolated from a patient prior to treatment harboring a triple-hit ABC-type DLBCL. PDX cells from passage four (PDX-4) were implanted into NSG mice. When tumors were palpable, mice were randomized to receive vehicle or 80 mg/kg/b.i.d. ribavarin intraperitoneally for 10 days. We isolated RNA from tumors treated with vehicle (n=2) or ribavarin (n=2) and performed mRNA-seq.
2016-01-11 | E-GEOD-63265 | biostudies-arrayexpress
Project description:Translation initiation is a rate-limiting step in protein synthesis. The eukaryotic translation initiation factor 4E (eIF4E) plays an essential role in the translation initiation process. However, how eIF4E-dependent translation initiation regulates plant growth and development remains not fully understood. In this study, we have found that Arabidopsis eIF4E proteins distribute both in the nucleus and cytoplasm, and only cytoplasmic eIF4E is implicated in the control of flowering time. Results of profiling the genome-wide translation by Ribo-tag sequencing further reveal that eIF4E may regulate plant flowering by affecting homeostatic translation of flowering-time genes, including the Central Oscillator Genes (COGs). Consistent with the hypothesis that transcription-translation feedback loop is the core mechanism to drive the oscillation of circadian clock, we show that the eIF4E-dependent translation modulates the rhythmic oscillation of protein abundance of the clock-related genes (CCGs). Together, our study provides mechanistic insights into how the protein translation regulates multiple developmental processed in Arabidopsis including circadian clock and photoperiodic flowering.
2023-10-25 | GSE245858 | GEO
Project description:Cyclin-dependent kinases 13 (CDK13) has been suggested to phosphorylate RNA polymerase II and is involved in transcriptional activation. However, whether CDK13 catalyzes other protein substrates and how CDK13 contributes to tumorigenesis remain largely unclear. Herein, we identify key translation machinery components 4E-BP1 and eIF4B as novel CDK13 substrates. CDK13 directly phosphorylates 4E-BP1 at Thr46 and eIF4B at Ser422 such that genetic or pharmacological inhibition of CDK13 perturbs RNA translation. Polysome profiling analysis shows that MYC oncoprotein synthesis depends on the CDK13-regulated translation in colorectal cancer (CRC), and CDK13 is required for CRC cell proliferation. As mTORC1 has been shown to phosphorylate the 4E-BP1 and eIF4B, knockdown or inhibition of CDK13 in combination with mTORC1 inhibitor rapamycin further dephosphorylates 4E-BP1 and eIF4B and blocks protein synthesis. As a result, dual inhibition of CDK13 and mTORC1 accelerated CRC cell death and again MYC were significantly downregulated upon combination treatment. These findings demonstrate a pro-tumorigenic role of CDK13 in CRC and shed light on the role of CDK13 in protein synthesis by direct phosphorylation of translation initiation factors. Therefore, therapeutic targeting of CDK13 alone or in combination with rapamycin may pave a new way for CRC treatment.
2023-03-09 | GSE224287 | GEO
Project description:4E-BP (eIF4E-BP) represses translation initiation by binding to the 5’cap-binding protein eIF4E and inhibiting its activity. Although 4E-BP has been shown to be important in growth control, stress response, cancer, neuronal activity and mammalian circadian rhythms, it is not understood how it preferentially represses a subset of mRNAs. We successfully used hyperTRIBE (Targets of RNA-binding proteins identified by editing) to identify in vivo 4E-BP mRNA targets in both Drosophila and mammals under conditions known to activate 4E-BP. The protein associates with specific mRNAs, and ribosome profiling data show that mTOR inhibition changes the translational efficiency of 4E-BP TRIBE targets compared to non-targets. In both systems, these targets have specific motifs and are enriched in translation-related pathways, which correlate well with the known activity of 4E-BP and suggest that it modulates the binding specificity of eIF4E and contributes to mTOR translational specificity.
2020-08-20 | GSE153346 | GEO