title: Inhibition of nonsense-mediated RNA decay by ER stress.
abstract: Nonsense-mediated RNA decay (NMD) selectively degrades mutated and aberrantly processed transcripts that contain premature termination codons (PTC). Cellular NMD activity is typically assessed using exogenous PTC-containing reporters. We overcame some inherently problematic aspects of assaying endogenous targets and developed a broadly applicable strategy to reliably and easily monitor changes in cellular NMD activity. Our new method was genetically validated for distinguishing NMD regulation from transcriptional control and alternative splicing regulation, and unexpectedly disclosed a different sensitivity of NMD targets to NMD inhibition. Applying this robust method for screening, we identified NMD-inhibiting stressors but also found that NMD inactivation was not universal to cellular stresses. The high sensitivity and broad dynamic range of our method revealed a strong correlation between NMD inhibition, endoplasmic reticulum (ER) stress, and polysome disassembly upon thapsigargin treatment in a temporal and dose-dependent manner. We found little evidence of calcium signaling mediating thapsigargin-induced NMD inhibition. Instead, we discovered that of the three unfolded protein response (UPR) pathways activated by thapsigargin, mainly protein kinase RNA-like endoplasmic reticulum kinase (PERK) was required for NMD inhibition. Finally, we showed that ER stress compounded TDP-43 depletion in the up-regulation of NMD isoforms that had been implicated in the pathogenic mechanisms of amyotrophic lateral sclerosis and frontotemporal dementia, and that the additive effect of ER stress was completely blocked by PERK deficiency.
authors.affiliation: Division of Biomedical Sciences, University of California, Riverside, California 92521, USA.
authors.forename: Zhelin
authors.initials: Z
authors.lastname: Li
authors.affiliation: Division of Biomedical Sciences, University of California, Riverside, California 92521, USA.
authors.forename: John K
authors.initials: JK
authors.lastname: Vuong
authors.affiliation: Division of Biomedical Sciences, University of California, Riverside, California 92521, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Division of Biomedical Sciences, University of California, Riverside, California 92521, USA.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Stork
authors.affiliation: Division of Biomedical Sciences, University of California, Riverside, California 92521, USA.
authors.forename: Sika
authors.initials: S
authors.lastname: Zheng
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D017398:Alternative Splicing / Q000187:drug effects*; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D018389:Codon, Nonsense; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics; D000076122:Disks Large Homolog 4 Protein; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D051528:Guanylate Kinases / Q000235:genetics / Q000378:metabolism; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000235:genetics / Q000378:metabolism; D057166:High-Throughput Screening Assays; D007211:Indoles / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D038941:Polypyrimidine Tract-Binding Protein / Q000235:genetics / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D020871:RNA Stability / Q000187:drug effects*; D016601:RNA-Binding Proteins; D015398:Signal Transduction; D019284:Thapsigargin / Q000494:pharmacology*; D019892:eIF-2 Kinase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D000225:Adenine; D002352:Carrier Proteins; D018389:Codon, Nonsense; D004268:DNA-Binding Proteins; D000076122:Disks Large Homolog 4 Protein; D004791:Enzyme Inhibitors; D051528:Guanylate Kinases; D034441:Heterogeneous-Nuclear Ribonucleoproteins; D007211:Indoles; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D038941:Polypyrimidine Tract-Binding Protein; D047428:Protein Kinase Inhibitors; D016601:RNA-Binding Proteins; D019284:Thapsigargin; D019892:eIF-2 Kinase; C576403:7-methyl-5-(1-((3-(trifluoromethyl)phenyl)acetyl)-2,3-dihydro-1H-indol-5-yl)-7H-pyrrolo(2,3-d)pyrimidin-4-amine; C501447:Dlg4 protein, mouse; C573992:Ptbp1 protein, mouse; C429773:Ptbp2 protein, mouse; C578077:Tardbp protein, mouse; C529977:Upf2 protein, mouse
keywords: ALS; ATF6α; FTD; Hnrnpl; IREα; NMD; PERK; Psd-95; Ptbp1; Ptbp2; Srsf11; Tdp-43; Tra2b; UPR; Upf2; alternative splicing; cellular stress; cryptic splicing