scholarly journals Coordinated Movements of Eukaryotic Translation Initiation Factors eIF1, eIF1A, and eIF5 Trigger Phosphate Release from eIF2 in Response to Start Codon Recognition by the Ribosomal Preinitiation Complex

2013 ◽  
Vol 288 (8) ◽  
pp. 5316-5329 ◽  
Author(s):  
Jagpreet S. Nanda ◽  
Adesh K. Saini ◽  
Antonio M. Muñoz ◽  
Alan G. Hinnebusch ◽  
Jon R. Lorsch
Keyword(s):  
Translation Initiation ◽  
Start Codon ◽  
Preinitiation Complex ◽  
Phosphate Release ◽  
Eukaryotic Translation ◽  
Initiation Factors ◽  
Codon Recognition ◽  
Translation Initiation Factors ◽  
Eukaryotic Translation Initiation ◽  
Eukaryotic Translation Initiation Factors

scholarly journals Dynamic competition between SARS-CoV-2 NSP1 and mRNA on the human ribosome inhibits translation initiation

2021 ◽  
Vol 118 (6) ◽  
pp. e2017715118
Author(s):  
Christopher P. Lapointe ◽  
Rosslyn Grosely ◽  
Alex G. Johnson ◽  
Jinfan Wang ◽  
Israel S. Fernández ◽  
...  
Keyword(s):  
Single Molecule ◽  
Translation Initiation ◽  
Ribosomal Subunit ◽  
Start Codon ◽  
Messenger Rnas ◽  
Eukaryotic Translation ◽  
Initiation Factors ◽  
Translation Initiation Factors ◽  
40S Ribosomal Subunit ◽  
Eukaryotic Translation Initiation Factors

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a beta-CoV that recently emerged as a human pathogen and is the causative agent of the COVID-19 pandemic. A molecular framework of how the virus manipulates host cellular machinery to facilitate infection remains unclear. Here, we focus on SARS-CoV-2 NSP1, which is proposed to be a virulence factor that inhibits protein synthesis by directly binding the human ribosome. We demonstrate biochemically that NSP1 inhibits translation of model human and SARS-CoV-2 messenger RNAs (mRNAs). NSP1 specifically binds to the small (40S) ribosomal subunit, which is required for translation inhibition. Using single-molecule fluorescence assays to monitor NSP1–40S subunit binding in real time, we determine that eukaryotic translation initiation factors (eIFs) allosterically modulate the interaction of NSP1 with ribosomal preinitiation complexes in the absence of mRNA. We further elucidate that NSP1 competes with RNA segments downstream of the start codon to bind the 40S subunit and that the protein is unable to associate rapidly with 80S ribosomes assembled on an mRNA. Collectively, our findings support a model where NSP1 proteins from viruses in at least two subgenera of beta-CoVs associate with the open head conformation of the 40S subunit to inhibit an early step of translation, by preventing accommodation of mRNA within the entry channel.

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