scholarly journals Translation Initiation Factor 3 Regulates Switching between Different Modes of Ribosomal Subunit Joining

2015 ◽  
Vol 427 (9) ◽  
pp. 1801-1818 ◽  
Author(s):  
Daniel D. MacDougall ◽  
Ruben L. Gonzalez
Keyword(s):  
Translation Initiation ◽  
Ribosomal Subunit ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Subunit Joining ◽  
Translation Initiation Factor 3

scholarly journals Coupled Release of Eukaryotic Translation Initiation Factors 5B and 1A from 80S Ribosomes following Subunit Joining

2007 ◽  
Vol 27 (6) ◽  
pp. 2384-2397 ◽  
Author(s):  
Jeanne M. Fringer ◽  
Michael G. Acker ◽  
Christie A. Fekete ◽  
Jon R. Lorsch ◽  
Thomas E. Dever
Keyword(s):  
Translation Initiation ◽  
Ribosomal Subunit ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Eukaryotic Translation ◽  
Cell Extracts ◽  
Eukaryotic Translation Initiation ◽  
Subunit Joining

ABSTRACT The translation initiation GTPase eukaryotic translation initiation factor 5B (eIF5B) binds to the factor eIF1A and catalyzes ribosomal subunit joining in vitro. We show that rapid depletion of eIF5B in Saccharomyces cerevisiae results in the accumulation of eIF1A and mRNA on 40S subunits in vivo, consistent with a defect in subunit joining. Substituting Ala for the last five residues in eIF1A (eIF1A-5A) impairs eIF5B binding to eIF1A in cell extracts and to 40S complexes in vivo. Consistently, overexpression of eIF5B suppresses the growth and translation initiation defects in yeast expressing eIF1A-5A, indicating that eIF1A helps recruit eIF5B to the 40S subunit prior to subunit joining. The GTPase-deficient eIF5B-T439A mutant accumulated on 80S complexes in vivo and was retained along with eIF1A on 80S complexes formed in vitro. Likewise, eIF5B and eIF1A remained associated with 80S complexes formed in the presence of nonhydrolyzable GDPNP, whereas these factors were released from the 80S complexes in assays containing GTP. We propose that eIF1A facilitates the binding of eIF5B to the 40S subunit to promote subunit joining. Following 80S complex formation, GTP hydrolysis by eIF5B enables the release of both eIF5B and eIF1A, and the ribosome enters the elongation phase of protein synthesis.

scholarly journals Structure of Human Mitochondrial Translation Initiation Factor 3 Bound to the Small Ribosomal Subunit

iScience ◽  
2019 ◽  
Vol 12 ◽  
pp. 76-86 ◽  
Author(s):  
Ravi K. Koripella ◽  
Manjuli R. Sharma ◽  
Md. Emdadul Haque ◽  
Paul Risteff ◽  
Linda L. Spremulli ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Ribosomal Subunit ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Mitochondrial Translation ◽  
Small Ribosomal Subunit ◽  
Translation Initiation Factor 3

scholarly journals Linking the 3′ Poly(A) Tail to the Subunit Joining Step of Translation Initiation: Relations of Pab1p, Eukaryotic Translation Initiation Factor 5B (Fun12p), and Ski2p-Slh1p

2001 ◽  
Vol 21 (15) ◽  
pp. 4900-4908 ◽  
Author(s):  
Anjanette Searfoss ◽  
Thomas E. Dever ◽  
Reed Wickner
Keyword(s):  
Translation Initiation ◽  
Ribosomal Subunit ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Rna Helicases ◽  
Eukaryotic Translation Initiation Factor ◽  
Eukaryotic Translation ◽  
Eukaryotic Translation Initiation ◽  
Subunit Joining

ABSTRACT The 3′ poly(A) structure improves translation of a eukaryotic mRNA by 50-fold in vivo. This enhancement has been suggested to be due to an interaction of the poly(A) binding protein, Pab1p, with eukaryotic translation initiation factor 4G (eIF4G). However, we find that mutation of eIF4G eliminating its interaction with Pab1p does not diminish the preference for poly(A)+ mRNA in vivo, indicating another role for poly(A). We show that either the absence of Fun12p (eIF5B), or a defect in eIF5, proteins involved in 60S ribosomal subunit joining, specifically reduces the translation of poly(A)+ mRNA, suggesting that poly(A) may have a role in promoting the joining step. Deletion of two nonessential putative RNA helicases (genes SKI2 and SLH1) makes poly(A) dispensable for translation. However, in the absence of Fun12p, eliminating Ski2p and Slh1p shows little enhancement of expression of non-poly(A) mRNA. This suggests that Ski2p and Slh1p block translation of non-poly(A) mRNA by an effect on Fun12p, possibly by affecting 60S subunit joining.

scholarly journals Control of Paip1-Eukayrotic Translation Initiation Factor 3 Interaction by Amino Acids through S6 Kinase

2014 ◽  
Vol 34 (6) ◽  
pp. 1046-1053 ◽  
Author(s):  
Y. Martineau ◽  
X. Wang ◽  
T. Alain ◽  
E. Petroulakis ◽  
D. Shahbazian ◽  
...  
Keyword(s):  
Amino Acids ◽  
Translation Initiation ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
S6 Kinase ◽  
Translation Initiation Factor 3

scholarly journals Translation Initiation Factor eIF3b Contains a Nine-Bladed β-Propeller and Interacts with the 40S Ribosomal Subunit

Structure ◽  
2014 ◽  
Vol 22 (6) ◽  
pp. 923-930 ◽  
Author(s):  
Yi Liu ◽  
Piotr Neumann ◽  
Bernhard Kuhle ◽  
Thomas Monecke ◽  
Stephanie Schell ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Ribosomal Subunit ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
40S Ribosomal Subunit
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