scholarly journals hCLE/RTRAF-HSPC117-DDX1-FAM98B: A New Cap-Binding Complex That Activates mRNA Translation

2019 ◽  
Vol 10 ◽  
Author(s):  
Alejandra Pazo ◽  
Alicia Pérez-González ◽  
Juan Carlos Oliveros ◽  
Maite Huarte ◽  
Juan Pablo Chavez ◽  
...  
Keyword(s):  
Mrna Translation ◽  
Cap Binding Complex

Control of protein translation by phosphorylation of the mRNA 5′-cap-binding complex

2007 ◽  
Vol 35 (6) ◽  
pp. 1634-1637 ◽  
Author(s):  
O.A. Pierrat ◽  
V. Mikitova ◽  
M.S. Bush ◽  
K.S. Browning ◽  
J.H. Doonan
Keyword(s):  
Environmental Changes ◽  
Mrna Translation ◽  
Cost Effective ◽  
Protein Translation ◽  
Mrna Levels ◽  
Control Of Gene Expression ◽  
Initiation Factors ◽  
Protein Levels ◽  
Translation Initiation Factors ◽  
Cap Binding Complex

Initiation of mRNA translation is a key regulatory step in the control of gene expression. Microarray analysis indicates that total mRNA levels do not always reflect protein levels, since mRNA association with polyribosomes is necessary for protein synthesis. Phosphorylation of translation initiation factors offers a cost-effective and rapid way to adapt to physiological and environmental changes, and there is increasing evidence that many of these factors are subject to multiple regulatory phosphorylation events. The present article focuses on the nature of reversible phosphorylation and the function of the 5′-cap-binding complex in plants.

scholarly journals Augmentation of nonsense mediated decay by rapamycin

2015 ◽  
Author(s):  
Rocio Teresa Martinez-Nunez ◽  
Doyle Coyne ◽  
Linnea Jansson ◽  
Miles Rush ◽  
Hanane Ennajdaoui ◽  
...  
Keyword(s):  
Steady State ◽  
Binding Proteins ◽  
Protein Composition ◽  
Mrna Translation ◽  
Dependent Manner ◽  
Mrna Isoforms ◽  
Nonsense Mediated Decay ◽  
Premature Termination Codons ◽  
Messenger Ribonucleoprotein ◽  
Cap Binding Complex

RNA surveillance by the Nonsense Mediated Decay (NMD) pathway eliminates potentially deleterious transcripts containing Premature Termination Codons (PTCs). The transition from a pioneering round of translation to steady state translation is hypothesized to be a major checkpoint in this process. One hallmark of mRNAs licensed for translation is the exchange of 7-methylguanosine cap binding proteins. However, mRNAs undergoing steady state translation are also NMD substrates, raising mechanistic questions about the NMD checkpoint. To test the role of cap binding proteins in NMD, we modulated the protein composition of cytoplasmic messenger ribonucleoprotein particles (mRNPs) with the naturally occurring macrolide rapamycin. We demonstrate that despite well-documented attenuation of cap-dependent mRNA translation, rapamycin can augment NMD. Rapamycin-treatment significantly reduces the levels of endogenous and exogenous PTC-containing mRNA isoforms in a dose- and UPF1- dependent manner. PTC-containing transcripts exhibit a shorter half-life upon rapamacyin-treatment as compared to non-PTC isoforms. Rapamycin also causes depletion of PTC-containing mRNA isoforms from polyribosomes, suggesting that actively translating ribosomes can transition between low and high NMD states. Importantly, mRNPs show depletion of eIF4E and retention of the nuclear Cap Binding Complex (CBC) in rapamycin-treated cells. Our data demonstrate that rapamycin potentiates pioneer-like mRNP context thereby decreasing NMD evasion.

Abstract B08: eIF4E3 forms a novel cap-binding complex for mRNA translation initiation.

2015 ◽  
Author(s):  
Ari L. Landon ◽  
Parameswary A Muniandy ◽  
Simone Houng ◽  
Amol Shetty ◽  
Kevin Becker ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Mrna Translation ◽  
Cap Binding Complex

scholarly journals NAD(P)H Quinone-Oxydoreductase 1 Protects Eukaryotic Translation Initiation Factor 4GI from Degradation by the Proteasome

2009 ◽  
Vol 30 (4) ◽  
pp. 1097-1105 ◽  
Author(s):  
Amandine Alard ◽  
Bertrand Fabre ◽  
Rodica Anesia ◽  
Catherine Marboeuf ◽  
Philippe Pierre ◽  
...  
Keyword(s):  
Steady State ◽  
Translation Initiation ◽  
Mrna Translation ◽  
State Level ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Steady State Level ◽  
Eukaryotic Translation ◽  
Eukaryotic Translation Initiation ◽  
Cap Binding Complex

ABSTRACT The eukaryotic translation initiation factor 4GI (eIF4GI) serves as a central adapter in cap-binding complex assembly. Although eIF4GI has been shown to be sensitive to proteasomal degradation, how the eIF4GI steady-state level is controlled remains unknown. Here, we show that eIF4GI exists in a complex with NAD(P)H quinone-oxydoreductase 1 (NQO1) in cell extracts. Treatment of cells with dicumarol (dicoumarol), a pharmacological inhibitor of NQO1 known to preclude NQO1 binding to its protein partners, provokes eIF4GI degradation by the proteasome. Consistently, the eIF4GI steady-state level also diminishes upon the silencing of NQO1 (by transfection with small interfering RNA), while eIF4GI accumulates upon the overexpression of NQO1 (by transfection with cDNA). We further reveal that treatment of cells with dicumarol frees eIF4GI from mRNA translation initiation complexes due to strong activation of its natural competitor, the translational repressor 4E-BP1. As a consequence of cap-binding complex dissociation and eIF4GI degradation, protein synthesis is dramatically inhibited. Finally, we show that the regulation of eIF4GI stability by the proteasome may be prominent under oxidative stress. Our findings assign NQO1 an original role in the regulation of mRNA translation via the control of eIF4GI stability by the proteasome.

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