title: Ire1-mediated decay in mammalian cells relies on mRNA sequence, structure, and translational status.
abstract: Endoplasmic reticulum (ER) stress occurs when misfolded proteins overwhelm the capacity of the ER, resulting in activation of the unfolded protein response (UPR). Ire1, an ER transmembrane nuclease and conserved transducer of the UPR, cleaves the mRNA encoding the transcription factor Xbp1 at a dual stem-loop (SL) structure, leading to Xbp1 splicing and activation. Ire1 also cleaves other mRNAs localized to the ER membrane through regulated Ire1-dependent decay (RIDD). We find that during acute ER stress in mammalian cells, Xbp1-like SLs within the target mRNAs are necessary for RIDD. Furthermore, depletion of Perk, a UPR transducer that attenuates translation during ER stress, inhibits RIDD in a substrate-specific manner. Artificially blocking translation of the SL region of target mRNAs fully restores RIDD in cells depleted of Perk, suggesting that ribosomes disrupt SL formation and/or Ire1 binding. This coordination between Perk and Ire1 may serve to spatially and temporally regulate RIDD.
authors.affiliation: Department of Biology and Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112.
authors.forename: Kristin
authors.initials: K
authors.lastname: Moore
authors.affiliation: Department of Biology and Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112 hollien@biology.utah.edu.
authors.forename: Julie
authors.initials: J
authors.lastname: Hollien
mesh_terms: D016475:3T3 Cells; D000818:Animals; D018929:Cell Culture Techniques; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D059865:Endoplasmic Reticulum Stress / Q000502:physiology*; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D056945:Hep G2 Cells; D006801:Humans; D055029:Inverted Repeat Sequences; D051379:Mice; D014176:Protein Biosynthesis; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012326:RNA Splicing; D020871:RNA Stability; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000071701:Regulatory Factor X Transcription Factors; D013329:Structure-Activity Relationship; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D056811:Unfolded Protein Response; D000071717:X-Box Binding Protein 1; D019892:eIF-2 Kinase / Q000235:genetics / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors; D000071717:X-Box Binding Protein 1; C000605543:XBP1 protein, human; C000605544:Xbp1 protein, mouse; C460640:EIF2AK3 protein, human; C528229:ERN1 protein, human; D017346:Protein Serine-Threonine Kinases; D019892:eIF-2 Kinase; D004722:Endoribonucleases