22 research outputs found
Discovery of Novel 1,4-Diacylpiperazines as Selective and Cell-Active eIF4A3 Inhibitors
Eukaryotic
initiation factor 4A3 (eIF4A3), a member of the DEAD-box
RNA helicase family, is one of the core components of the exon junction
complex (EJC). The EJC is known to be involved in a variety of RNA
metabolic processes typified by nonsense-mediated RNA decay (NMD).
In order to identify molecular probes to investigate the functions
and therapeutic relevance of eIF4A3, a search for selective eIF4A3
inhibitors was conducted. Through the chemical optimization of 1,4-diacylpiperazine
derivatives identified via high-throughput screening (HTS), we discovered
the first reported selective eIF4A3 inhibitor <b>53a</b> exhibiting
cellular NMD inhibitory activity. A surface plasmon resonance (SPR)
biosensing assay ascertained the direct binding of <b>53a</b> and its analog <b>52a</b> to eIF4A3 and revealed that the
binding occurs at a non-ATP binding site. Compounds <b>52a</b> and <b>53a</b> represent novel molecular probes for further
study of eIF4A3, the EJC, and NMD
Discovery of Novel 1,4-Diacylpiperazines as Selective and Cell-Active eIF4A3 Inhibitors
Eukaryotic
initiation factor 4A3 (eIF4A3), a member of the DEAD-box
RNA helicase family, is one of the core components of the exon junction
complex (EJC). The EJC is known to be involved in a variety of RNA
metabolic processes typified by nonsense-mediated RNA decay (NMD).
In order to identify molecular probes to investigate the functions
and therapeutic relevance of eIF4A3, a search for selective eIF4A3
inhibitors was conducted. Through the chemical optimization of 1,4-diacylpiperazine
derivatives identified via high-throughput screening (HTS), we discovered
the first reported selective eIF4A3 inhibitor <b>53a</b> exhibiting
cellular NMD inhibitory activity. A surface plasmon resonance (SPR)
biosensing assay ascertained the direct binding of <b>53a</b> and its analog <b>52a</b> to eIF4A3 and revealed that the
binding occurs at a non-ATP binding site. Compounds <b>52a</b> and <b>53a</b> represent novel molecular probes for further
study of eIF4A3, the EJC, and NMD
Discovery of Novel 1,4-Diacylpiperazines as Selective and Cell-Active eIF4A3 Inhibitors
Eukaryotic
initiation factor 4A3 (eIF4A3), a member of the DEAD-box
RNA helicase family, is one of the core components of the exon junction
complex (EJC). The EJC is known to be involved in a variety of RNA
metabolic processes typified by nonsense-mediated RNA decay (NMD).
In order to identify molecular probes to investigate the functions
and therapeutic relevance of eIF4A3, a search for selective eIF4A3
inhibitors was conducted. Through the chemical optimization of 1,4-diacylpiperazine
derivatives identified via high-throughput screening (HTS), we discovered
the first reported selective eIF4A3 inhibitor <b>53a</b> exhibiting
cellular NMD inhibitory activity. A surface plasmon resonance (SPR)
biosensing assay ascertained the direct binding of <b>53a</b> and its analog <b>52a</b> to eIF4A3 and revealed that the
binding occurs at a non-ATP binding site. Compounds <b>52a</b> and <b>53a</b> represent novel molecular probes for further
study of eIF4A3, the EJC, and NMD
Discovery and Characterization of a Eukaryotic Initiation Factor 4A-3-Selective Inhibitor That Suppresses Nonsense-Mediated mRNA Decay
Eukaryotic
initiation factor 4A-3 (eIF4A3) is an Asp-Glu-Ala-Asp
(DEAD) box-family adenosine triphosphate (ATP)-dependent RNA helicase.
Subtypes eIF4A1 and eIF4A2 are required for translation initiation,
but eIF4A3 participates in the exon junction complex (EJC) and functions
in RNA metabolism including nonsense-mediated RNA decay (NMD). No
small molecules for NMD inhibition <i>via</i> selective
inhibition of eIF4A3 have been discovered. Here, we identified allosteric
eIF4A3 inhibitors from a high-throughput screening campaign. Chemical
optimization of the lead compounds based on ATPase activity yielded
compound <b>2</b>, which exhibited noncompetitive inhibition
with ATP or RNA and high selectivity for eIF4A3 over other helicases.
The optimized compounds suppressed the helicase activity of eIF4A3
in an ATPase-dependent manner. Hydrogen/deuterium exchange mass spectrometry
demonstrated that the deuterium-incorporation pattern of compound <b>2</b> overlapped with that of an allosteric pan-eIF4A inhibitor,
hippuristanol, suggesting that compound <b>2</b> binds to an
allosteric region on eIF4A3. We examined NMD activity using a luciferase-based
cellular reporter system and a quantitative real-time polymerase chain-reaction-based
cellular system to monitor levels of endogenous NMD substrates. NMD
suppression by the compounds correlated positively with their ATPase-inhibitory
activity. In conclusion, we developed a novel eIF4A3 inhibitor that
targets the EJC. The optimized chemical probes represent useful tools
for understanding the functions of eIF4A3 in RNA homeostasis