scholarly journals Interaction between Eukaryotic Initiation Factors 1A and 5B Is Required for Efficient Ribosomal Subunit Joining

2006 ◽  
Vol 281 (13) ◽  
pp. 8469-8475 ◽  
Author(s):  
Michael G. Acker ◽  
Byung-Sik Shin ◽  
Thomas E. Dever ◽  
Jon R. Lorsch
Keyword(s):  
Ribosomal Subunit ◽  
Initiation Factors ◽  
Eukaryotic Initiation Factors ◽  
Subunit Joining

scholarly journals Structural differences in translation initiation between pathogenic trypanosomatids and their mammalian hosts

2019 ◽  
Author(s):  
Anthony Bochler ◽  
Jailson Brito Querido ◽  
Terezie Prilepskaja ◽  
Heddy Soufari ◽  
Angelita Simonetti ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Trypanosoma Cruzi ◽  
Translation Initiation ◽  
Ribosomal Subunit ◽  
Mrna Translation ◽  
Mass Spectrometry Data ◽  
Initiation Complex ◽  
Initiation Factors ◽  
Eukaryotic Initiation Factors ◽  
Structural Differences

SUMMARYCanonical mRNA translation in eukaryotes begins with the formation of the 43S pre-initiation complex (PIC). Its assembly requires the binding of several eukaryotic initiation factors (eIF 1, 1A, 2, 3 and 5), Met-tRNAiMet and the small ribosomal subunit (40S). Compared to their mammalian hosts, trypanosomatids present significant structural differences in their 40S suggesting substantial variability in translation initiation. Here we determined the structure of the 43S PIC from Trypanosoma cruzi, the parasite causing the Chagas disease. Our structure shows numerous specific features, such as the variant eIF3 structure and its unique interactions with the large rRNA ESs 9S, 7S and 6S, and the association of a kinetoplastid-specific ~245 kDa DDX60-like helicase. It also revealed the so-far-elusive 40S-binding site of the eIF5 C-terminal domain and the structures of key terminal tails of several conserved eIFs underlying their activities within the PIC. Our results are corroborated by GST-pulldown assays in both human and T. cruzi and mass-spectrometry data.

scholarly journals eIF5B and eIF1A remodel human translation initiation complexes to mediate ribosomal subunit joining

2021 ◽  
Author(s):  
Christopher P. Lapointe ◽  
Rosslyn Grosely ◽  
Masaaki Sokabe ◽  
Carlos Alvarado ◽  
Jinfan Wang ◽  
...  
Keyword(s):  
Single Molecule ◽  
Translation Initiation ◽  
Messenger Rna ◽  
Ribosomal Subunit ◽  
Ribosomal Subunits ◽  
Initiation Factors ◽  
Architectural Framework ◽  
Subunit Joining ◽  
Structural Methods

Joining of the ribosomal subunits at a translation start site on a messenger RNA during initiation commits the ribosome to synthesize a protein. Here, we combined single-molecule spectroscopy and structural methods using an in vitro reconstituted system to examine how the human ribosomal subunits join. Single-molecule fluorescence revealed when universally-conserved eukaryotic initiation factors (eIFs) eIF1A and eIF5B associate with and depart from initiation complexes. Guided by single-molecule dynamics, we examined initiation complexes that contained both eIF1A and eIF5B using single-particle electron cryo-microscopy. The resulting structure illuminated how eukaryote-specific contacts between eIF1A and eIF5B remodel the initiation complex to orient initiator tRNA in a conformation compatible with ribosomal subunit joining. Collectively, our findings provide a quantitative and architectural framework for the molecular choreography orchestrated by eIF1A and eIF5B during human translation initiation.

X-ray structures of eIF5B and the eIF5B–eIF1A complex: the conformational flexibility of eIF5B is restricted on the ribosome by interaction with eIF1A

2014 ◽  
Vol 70 (12) ◽  
pp. 3090-3098 ◽  
Author(s):  
Aiping Zheng ◽  
Jian Yu ◽  
Reo Yamamoto ◽  
Toyoyuki Ose ◽  
Isao Tanaka ◽  
...  
Keyword(s):  
Ribosomal Subunit ◽  
Structural Flexibility ◽  
80S Ribosome ◽  
Core Domain ◽  
Initiation Factors ◽  
Translation Initiation Factors ◽  
Density Map ◽  
The Individual ◽  
Subunit Joining ◽  
Electron Density Map

eIF5B and eIF1A are two translation-initiation factors that are universally conserved among all kingdoms. They show a unique interaction in eukaryotes which is important for ribosomal subunit joining. Here, the structures of two isolated forms of yeast eIF5B and of the eIF5B–eIF1A complex (eIF1A and eIF5B do not contain the respective N-terminal domains) are reported. The eIF5B–eIF1A structure shows that the C-terminal tail of eIF1A binds to eIF5B domain IV, while the core domain of eIF1A is invisible in the electron-density map. Although the individual domains in all structures of eIF5B or archaeal IF5B (aIF5B) are similar, their domain arrangements are significantly different, indicating high structural flexibility, which is advantageous for conformational change during ribosomal subunit joining. Based on these structures, models of eIF5B, eIF1A and tRNAiMeton the 80S ribosome were built. The models suggest that the interaction between the eIF1A C-terminal tail and eIF5B helps tRNAiMetto bind to eIF5B domain IV, thus preventing tRNAiMetdissociation, stabilizing the interface for subunit joining and providing a checkpoint for correct ribosome assembly.

scholarly journals RNA-stimulated ATPase activity of eukaryotic initiation factors.

1984 ◽  
Vol 259 (13) ◽  
pp. 8648-8654 ◽  
Author(s):  
J A Grifo ◽  
R D Abramson ◽  
C A Satler ◽  
W C Merrick
Keyword(s):  
Atpase Activity ◽  
Initiation Factors ◽  
Eukaryotic Initiation Factors
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