Abstract
In mammals, nonsense-mediated mRNA decay (NMD) is a quality-control mechanism that degrades mRNA harboring a premature termination codon to prevent the synthesis of truncated proteins. To gain insight into the NMD mechanism, we identified NMD inhibitor 1 (NMDI 1) as a small molecule inhibitor of the NMD pathway. We characterized the mode of action of this compound and demonstrated that it acts upstream of hUPF1. NMDI 1 induced the loss of interactions between hSMG5 and hUPF1 and the stabilization of hyperphosphorylated isoforms of hUPF1. Incubation of cells with NMDI 1 allowed us to demonstrate that NMD factors and mRNAs subject to NMD transit through processing bodies (P-bodies), as is the case in yeast. The results suggest a model in which mRNA and NMD factors are sequentially recruited to P-bodies.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Carrier Proteins / metabolism
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Codon, Nonsense / metabolism*
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Cytoplasmic Structures / drug effects*
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Cytoplasmic Structures / metabolism*
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Down-Regulation / drug effects
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Exoribonucleases / genetics
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HeLa Cells
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Humans
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Indoles / pharmacology*
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Microtubule-Associated Proteins / genetics
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Models, Biological
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Mutant Proteins / metabolism
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Phosphorylation / drug effects
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Protein Binding / drug effects
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Protein Isoforms / metabolism
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Protein Transport / drug effects
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RNA Helicases
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RNA Stability / drug effects*
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RNA, Messenger / metabolism
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RNA-Binding Proteins / metabolism
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Thermodynamics
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Trans-Activators / metabolism
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Transcription Factors / genetics
Substances
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Carrier Proteins
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Codon, Nonsense
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Indoles
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Microtubule-Associated Proteins
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Mutant Proteins
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Protein Isoforms
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RNA, Messenger
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RNA-Binding Proteins
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SMG5 protein, human
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Trans-Activators
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Transcription Factors
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UPF2 protein, human
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indole
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Exoribonucleases
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XRN1 protein, human
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RNA Helicases
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UPF1 protein, human