Document Detail

Evidence for a functionally relevant rocaglamide binding site on the eIF4A:RNA complex.
MedLine Citation:
PMID:  23614532     Owner:  NLM     Status:  Publisher    
Translation initiation is an emerging target in oncology and neurobiology indications. Naturally derived and synthetic rocaglamide scaffolds have been used to interrogate this pathway, however, there is uncertainty regarding their precise mechanism(s) of action. We exploited the genetic tractability of yeast to define the primary effect of both a natural and a synthetic rocaglamide in a cellular context, and characterized the molecular target using biochemical studies and in silico modeling. Chemogenomic profiling and mutagenesis in yeast identified the eIF (eukaryotic Initiation Factor) 4A helicase homologue as the primary molecular target of rocaglamides, and defined a discrete set of residues near the RNA binding motif which confer resistance to both compounds. Three of the eIF4A mutations were characterized regarding their functional consequences on activity and response to rocaglamide inhibition. These data support a model whereby rocaglamides stabilize an eIF4A-RNA interaction to either alter the level and/or impair the activity of the eIF4F complex. Furthermore, in silico modeling supports the annotation of a binding pocket delineated by the RNA substrate and the residues identified from our mutagenesis screen. As expected from the high degree of conservation of the eukaryotic translation pathway, these observations are consistent with previous observations in mammalian model systems. Importantly, we demonstrate that the chemically distinct silvestrol and synthetic rocaglamides share a common mechanism of action, which will be critical for optimization of physiologically stable derivatives. Finally, these data confirm the value of the rocaglamide scaffold for exploring the impact of translational modulation on disease.
Heather Sadlish; Gabriela Galicia-Vazquez; C Gregory Paris; Thomas Aust; Bhupinder Bhullar; Lena Chang; Stephen B Helliwell; Dominic Hoepfner; Britta Knapp; Ralph Riedl; Silvio Roggo; Sven Schuierer; Christian Studer; John A Porco; Jerry Pelletier; N Rao Movva
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-4-24
Journal Detail:
Title:  ACS chemical biology     Volume:  -     ISSN:  1554-8937     ISO Abbreviation:  ACS Chem. Biol.     Publication Date:  2013 Apr 
Date Detail:
Created Date:  2013-4-25     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101282906     Medline TA:  ACS Chem Biol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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