scholarly journals Interactome Mapping of eIF3A in a Colon Cancer and an Immortalized Embryonic Cell Line Using Proximity-Dependent Biotin Identification

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1293
Author(s):  
Diep-Khanh Vo ◽  
Alexander Engler ◽  
Darko Stoimenovski ◽  
Roland Hartig ◽  
Thilo Kaehne ◽  
...  
Keyword(s):  
Er Stress ◽  
Cell Line ◽  
Translation Initiation ◽  
Rna Binding ◽  
Embryonic Cell ◽  
Initiation Factor ◽  
Translation Efficiency ◽  
Interacting Proteins ◽  
Eukaryotic Initiation Factor ◽  
Embryonic Cell Line

Translation initiation comprises complex interactions of eukaryotic initiation factor (eIF) subunits and the structural elements of the mRNAs. Translation initiation is a key process for building the cell’s proteome. It not only determines the total amount of protein synthesized but also controls the translation efficiency for individual transcripts, which is important for cancer or ageing. Thus, understanding protein interactions during translation initiation is one key that contributes to understanding how the eIF subunit composition influences translation or other pathways not yet attributed to eIFs. We applied the BioID technique to two rapidly dividing cell lines (the immortalized embryonic cell line HEK-293T and the colon carcinoma cell line HCT-166) in order to identify interacting proteins of eIF3A, a core subunit of the eukaryotic initiation factor 3 complex. We identified a total of 84 interacting proteins, with very few proteins being specific to one cell line. When protein biosynthesis was blocked by thapsigargin-induced endoplasmic reticulum (ER) stress, the interacting proteins were considerably smaller in number. In terms of gene ontology, although eIF3A interactors are mainly part of the translation machinery, protein folding and RNA binding were also found. Cells suffering from ER-stress show a few remaining interactors which are mainly ribosomal proteins or involved in RNA-binding.

scholarly journals Epstein-Barr Virus Protein EB2 Stimulates Translation Initiation of mRNAs through Direct Interactions with both Poly(A)-Binding Protein and Eukaryotic Initiation Factor 4G

2017 ◽  
Vol 92 (3) ◽  
Author(s):  
Fabrice Mure ◽  
Baptiste Panthu ◽  
Isabelle Zanella-Cléon ◽  
Frédéric Delolme ◽  
Evelyne Manet ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Epstein Barr Virus ◽  
Rna Binding ◽  
Binding Protein ◽  
Initiation Factor ◽  
Translation Efficiency ◽  
Eukaryotic Initiation Factor ◽  
Barr Virus ◽  
Intronless Genes ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) expresses several mRNAs produced from intronless genes that could potentially be unfavorably translated compared to cellular spliced mRNAs. To overcome this situation, the virus encodes an RNA-binding protein (RBP) called EB2, which was previously found to both facilitate the export of nuclear mRNAs and increase their translational yield. Here, we show that EB2 binds both nuclear and cytoplasmic cap-binding complexes (CBC and eukaryotic initiation factor 4F [eIF4F], respectively) as well as the poly(A)-binding protein (PABP) to enhance translation initiation of a given messenger ribonucleoparticle (mRNP). Interestingly, such an effect can be obtained only if EB2 is initially bound to the native mRNPs in the nucleus. We also demonstrate that the EB2-eIF4F-PABP association renders translation of these mRNPs less sensitive to translation initiation inhibitors. Taken together, our data suggest that EB2 binds and stabilizes cap-binding complexes in order to increase mRNP translation and furthermore demonstrate the importance of the mRNP assembly process in the nucleus to promote protein synthesis in the cytoplasm. IMPORTANCE Most herpesvirus early and late genes are devoid of introns. However, it is now well documented that mRNA splicing facilitates recruitment on the mRNAs of cellular factors involved in nuclear mRNA export and translation efficiency. To overcome the absence of splicing of herpesvirus mRNAs, a viral protein, EB2 in the case of Epstein-Barr virus, is produced to facilitate the cytoplasmic accumulation of viral mRNAs. Although we previously showed that EB2 also specifically enhances translation of its target mRNAs, the mechanism was unknown. Here, we show that EB2 first is recruited to the mRNA cap structure in the nucleus and then interacts with the proteins eIF4G and PABP to enhance the initiation step of translation.

scholarly journals Acute Regulation of Translation Initiation by Gonadotropin-Releasing Hormone in the Gonadotrope Cell Line LβT2

2004 ◽  
Vol 18 (5) ◽  
pp. 1301-1312 ◽  
Author(s):  
Kathryn A. Nguyen ◽  
Sharon J. Santos ◽  
Marit K. Kreidel ◽  
Alejandro L. Diaz ◽  
Rodolfo Rey ◽  
...  
Keyword(s):  
Cell Line ◽  
Translation Initiation ◽  
Translational Control ◽  
Promoter Activity ◽  
Gnrh Receptor ◽  
Initiation Factor ◽  
Dependent Manner ◽  
Eukaryotic Initiation Factor ◽  
Western Blots ◽  
Stimulation Of

Abstract The hypothalamic neuropeptide hormone GnRH is the central regulator of reproductive function. GnRH stimulates the synthesis and release of the gonadotropins LH and FSH by the gonadotropes of the anterior pituitary through activation of the G-protein-coupled GnRH receptor. In this study, we investigated the role of translational control of hormone synthesis by the GnRH receptor in the novel gonadotrope cell line LβT2. Using immunohistochemical and RIA studies with this model, we show that acute GnRH-induced synthesis and secretion of LH are dependent upon new protein synthesis but not new mRNA synthesis. We examined the response to GnRH and found that activation of cap-dependent translation occurs within 4 h. LHβ promoter activity was also examined, and we found no increases in LHβ promoter activity after 6 h of GnRH stimulation. Additionally, we show that increased phosphorylation of translation initiation proteins, 4E-binding protein 1, eukaryotic initiation factor 4E, and eukaryotic initiation factor 4G, occur in a dose- and time-dependent manner in response to GnRH stimulation. Quantitative luminescent image analysis of Western blots shows that 10 nm GnRH is sufficient to cause a maximal increase in factor phosphorylation, and maximal responses occur within 30 min of stimulation. Further, we demonstrate that the MAPK kinase inhibitor, PD 98059, abolishes the GnRH-mediated stimulation of a cap-dependent translation reporter. More specifically, we demonstrate that PD 98059 abolishes the GnRH-mediated stimulation of a downstream target of the ERK pathway, MAPK-interacting kinase. Based on these findings, we conclude that acute GnRH stimulation of LβT2 cells increases translation initiation through ERK signaling. This may contribute to the acute increases in LHβ subunit production.

scholarly journals CELF1 is an EIF4E binding protein that promotes translation of epithelial-mesenchymal transition effector mRNAs

2019 ◽  
Author(s):  
Arindam Chaudhury ◽  
Rituraj Pal ◽  
Natee Kongchan ◽  
Na Zhao ◽  
Yingmin Zhu ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Mammalian Cells ◽  
Rna Binding ◽  
Epithelial Mesenchymal Transition ◽  
Binding Protein ◽  
Mrna Translation ◽  
Scaffolding Protein ◽  
Initiation Factor ◽  
Eukaryotic Initiation Factor ◽  
Mesenchymal Transition

AbstractMounting evidence is revealing a granularity within gene regulation that occurs at the level of mRNA translation. Within mammalian cells, canonical cap-dependent mRNA translation is dependent upon the interaction between the m7G cap-binding protein eukaryotic initiation factor 4E (eIF4E) and the scaffolding protein eukaryotic initiation factor 4G (eIF4G), the latter of which facilitates pre-translation initiation complex assembly, mRNA circularization, and ultimately ribosomal scanning. In breast epithelial cells, we previously demonstrated that the CELF1 RNA-binding protein promotes the translation of epithelial to mesenchymal transition (EMT) effector mRNAs containing GU-rich elements (GREs) within their 3’ untranslated regions (UTRs). Here we show that within this context, CELF1 directly binds to both the eIF4E cap-binding protein and Poly(A) binding protein (PABP), promoting translation of GRE-containing mRNAs in mesenchymal cells. Disruption of this CELF1/eIF4E interaction inhibits both EMT induction and experimental metastasis. Our findings illustrate a novel way in which non-canonical mechanisms of translation initiation underlie transitional cellular states within the context of development or human disease.

Characterization of mutant spectra generated by a forward mutational assay for geneA of ?X174 from ENU-treated transgenic mouse embryonic cell line PX-2

2002 ◽  
Vol 39 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Carrie R. Valentine ◽  
Beverly A. Montgomery ◽  
Scott G. Miller ◽  
Robert R. Delongchamp ◽  
Bentley A. Fane ◽  
...  
Keyword(s):  
Cell Line ◽  
Transgenic Mouse ◽  
Embryonic Cell ◽  
Embryonic Cell Line

scholarly journals Eukaryotic initiation factor EIF-3.G augments mRNA translation efficiency to regulate neuronal activity

2021 ◽  
Author(s):  
Stephen M Blazie ◽  
Seika Takayanagi-Kiya ◽  
Katherine A McCulloch ◽  
Yishi Jin
Keyword(s):  
Rna Binding ◽  
Mrna Translation ◽  
Initiation Factor ◽  
Translation Efficiency ◽  
Dependent Manner ◽  
Control Activity ◽  
C Elegans ◽  
Protein Levels ◽  
Neuronal Protein

AbstractThe translation initiation complex eIF3 imparts specialized functions to regulate protein expression. However, understanding of eIF3 activities in neurons remains limited despite widespread dysregulation of eIF3 subunits in neurological disorders. Here, we report a selective role of theC. elegansRNA-binding subunit EIF-3.G in shaping the neuronal protein landscape. We identify a missense mutation in the conserved Zinc-Finger (ZF) of EIF-3.G that acts in a gain-of-function manner to dampen neuronal hyperexcitation. Using neuron type-specific seCLIP, we systematically mapped EIF-3.G-mRNA interactions and identified EIF-3.G occupancy on GC-rich 5′UTRs of a select set of mRNAs enriched in activity-dependent functions. We demonstrate that the ZF mutation in EIF-3.G alters translation in a 5′UTR dependent manner. Our study reveals anin vivomechanism for eIF3 in governing neuronal protein levels to control activity states and offers insights into how eIF3 dysregulation contributes to neuronal disorders.

Some determinants of cellular adhesiveness in an embryonic cell line fromDrosophila melanogaster

1985 ◽  
Vol 234 (1) ◽  
pp. 47-55 ◽  
Author(s):  
Anne Fausto-Sterling ◽  
F. A. Muckenthaler ◽  
Lily Hsieh ◽  
Peter L. Rosenblatt
Keyword(s):  
Cell Line ◽  
Embryonic Cell ◽  
Embryonic Cell Line
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