title: Stimulators of translation identified during a small molecule screening campaign.
abstract: In screening a library of natural and synthetic products for eukaryotic translation modulators, we identified two natural products, isohymenialdisine and hymenialdisine, that exhibit stimulatory effects on translation. The characterization of these compounds led to the insight that mRNA used to program the translation extracts during high-throughput assay setup was leading to phosphorylation of eIF2α, a potent negative regulatory event that is mediated by one of four kinases. We identified double-stranded RNA-dependent protein kinase (PKR) as the eIF2α kinase that was being activated by exogenously added mRNA template. Characterization of the mode of action of isohymenialdisine revealed that it directly acts on PKR by inhibiting autophosphorylation, perturbs the PKR-eIF2α phosphorylation axis, and can be modeled into the PKR ATP binding site. Our results identify a source of "false positives" for high-throughput screen campaigns using translation extracts, raising a cautionary note for this type of screen.
authors: Unkyung
authors: U
authors: Shin
authors: David E
authors: DE
authors: Williams
authors: Dima
authors: D
authors: Kozakov
authors: David R
authors: DR
authors: Hall
authors: Dmitri
authors: D
authors: Beglov
authors: Sandor
authors: S
authors: Vajda
authors: Raymond J
authors: RJ
authors: Andersen
authors: Jerry
authors: J
authors: Pelletier
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001381:Azepines / Q000494:pharmacology; D004353:Drug Evaluation, Preclinical; D057166:High-Throughput Screening Assays; D008958:Models, Molecular; D014176:Protein Biosynthesis / Q000187:drug effects*; D011487:Protein Conformation; D011758:Pyrroles / Q000494:pharmacology; D054852:Small Molecule Libraries / Q000494:pharmacology*; D019892:eIF-2 Kinase / Q000737:chemistry / Q000378:metabolism
chemical_list: D001381:Azepines; D011758:Pyrroles; D054852:Small Molecule Libraries; D000255:Adenosine Triphosphate; C107079:hymenialdisine; D019892:eIF-2 Kinase