Characterization of two homologs of Ire1p, a kinase/endoribonuclease in yeast, in Arabidopsis thaliana

Noh, Seung-Jae; Kwon, Chang Seob; Chung, Won Sang

doi:10.1016/s0167-4781(02)00237-3

Cited by 64 publications

(62 citation statements)

References 15 publications

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“…They also demonstrated functional complementation of the Arabidopsis IRE1a luminal domain (sensor domain) in yeast and that the plant IRE1a has autophosphorylation activity in vitro, but they were unable to demonstrate endonuclease activity. Noh et al (2002) confirmed several observations made by Koizumi et al (2001), but they also attempted to show unsuccessfully whether IRE1a could splice yeast Hac1 RNA in tunicamycin-treated Arabidopsis protoplasts. Similar results were also reported in rice (Oryza sativa; Okushima et al, 2002).…”

Section: Eradsupporting

confidence: 68%

Endoplasmic Reticulum Protein Quality Control and Its Relationship to Environmental Stress Responses in Plants

2010

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The endoplasmic reticulum (ER) has a sophisticated quality control (QC) system to eliminate improperly folded proteins from the secretory pathway. Given that protein folding is such a fastidious process and subject to adverse environmental conditions, the ER QC system appears to have been usurped to serve as an environmental sensor and responder in plants. Under stressful conditions, the ER protein folding machinery reaches a limit as the demands for protein folding exceed the capacity of the system. Under these conditions, misfolded or unfolded proteins accumulate in the ER, triggering an unfolded protein response (UPR). UPR mitigates ER stress by upregulating the expression of genes encoding components of the protein folding machinery or the ER-associated degradation system. In Arabidopsis thaliana, ER stress is sensed and stress signals are transduced by membrane-bound transcription factors, which are activated and mobilized under environmental stress conditions. Under acute or chronic stress conditions, UPR can also lead to apoptosis or programmed cell death. Despite recent progress in our understanding of plant protein QC, discovering how different environmental conditions are perceived is one of the major challenges in understanding this system. Since the ER QC system is one among many stress response systems in plants, another major challenge is determining the extent to which the ER QC system contributes to various stress responses in plants.

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Section: Eradsupporting

confidence: 68%

Endoplasmic Reticulum Protein Quality Control and Its Relationship to Environmental Stress Responses in Plants

2010

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“…ca/efp/cgi-bin/efpWeb.cgi), both Arabidopsis IRE1 genes are expressed at low levels. IRE1b is more generally expressed throughout the plant, while IRE1a is more locally expressed in embryos and seeds (17,18). The activity capable of splicing bZIP60 mRNA did not appear to be localized to a specific region of the seedling because splicing activity and BIP3 induction were observed following 2 h of DTT treatment in seedling shoots, hypocotyls and roots (Fig.…”

Section: Arabidopsis Bzip60mentioning

confidence: 98%

“…Koizumi et al (17) demonstrated functional complementation of the Arabidopsis luminal domain (sensor domain) in yeast and that the plant IRE1a has autophosphorylation activity in vitro, but they were unable to demonstrate splicing. Noh et al (18) attempted, but were unsuccessful, in showing that IRE1a could splice yeast Hac1 RNA in Arabidopsis protoplasts.…”

mentioning

confidence: 99%

Heat induces the splicing by IRE1 of a mRNA encoding a transcription factor involved in the unfolded protein response in Arabidopsis

Deng

Humbert

Liu

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

409

487

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Adverse environmental conditions produce endoplasmic reticulum (ER) stress in plants. In response to heat or ER stress agents, Arabidopsis seedlings mitigate stress damage by activating ERassociated transcription factors and a RNA splicing factor, IRE1b. IRE1b splices the mRNA-encoding bZIP60, a basic leucine-zipper domain containing transcription factor associated with the unfolded protein response in plants. bZIP60 is required for the upregulation of BINDING PROTEIN3 (BIP3) in response to ER stress, and loss-of-function mutations in IRE1b or point mutations in the splicing site of bZIP60 mRNA are defective in BIP3 induction. These findings demonstrate that bZIP60 in plants is activated by RNA splicing and afford opportunities for monitoring and modulating stress responses in plants.abiotic stress | heat stress | RNA splicing | signal transduction H eat and drought tolerance are some of the most complex and important adaptive traits in plants. These stresses are foremost in placing limits on plant productivity worldwide, and tolerance to these stresses are among the most highly sought after traits in crops (1), particularly in the face of climate change.The unfolded protein response (UPR) in eukaryotes is an ER stress response that activates three different classes of membraneassociated sensor transducers in mammalian cells-activating transcription factor 6 (ATF6), inositol-requiring enzyme-1 (IRE1) and protein kinase RNA (PKR)-like ER kinase. Yeast has only one ER stress transducer, IRE1; nonetheless, this factor sets off a massive UPR by triggering the expression of >5% of genes in the yeast genome. Many of these encode chaperones and ER-associated protein degradation components (2). IRE1 in yeast and mammalian cells acts by splicing a messenger RNA encoding a transcription factor that, then in turn, activates the expression of stress response genes (see recent reviews; refs. 3-5). Yeast cells splice an mRNA encoding a transcription factor called Hac1p (6, 7). The unspliced form of the Hac1 messenger RNA attenuates its own translation, and splicing relieves the translational repression (8).IRE1-mediated splicing is unconventional because mRNA splicing normally occurs in the nucleus, not in the cytoplasm (9). IRE1 is a type I membrane-spanning protein situated in the ER with its N terminus facing the ER lumen and its C terminus, which possesses catalytic functions, facing the cytosol. IRE1 is regarded as a dual functional enzyme possessing both serine/threonine protein kinase and endoribonuclease activity (10). Upon activation, the IRE1 dimer undergoes autotransphosphorylation in which one monomer phosphorylates the other (11). Through the analysis of the structure of the cytosolic domain of IRE1, Lee et al. (12) found that dimerization brings together the kinase domains in a face-to-face manner that would seemingly facilitate autotransphosphorylation.Autotransphosphorylation is then thought to open a nucleotide-binding site that, when occupied, produces a conformational change in the cytosolic domain so as t...

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“…Analysis of BiP promoters in Arabidopsis (Arabidopsis thaliana) has shown conservation of cis-elements between plant and mammalian cells (Noh et al 2003;Oh et al 2003). Although proteins homologous to yeast and mammalian IRE1 have been reported in Arabidopsis and rice (Oryza sativa) (Koizumi et al 2001;Noh et al 2002;Okushima et al 2002), their involvement in the ER stress signaling pathway has not yet been determined; neither has any mRNA that is spliced been identified. Arabidopsis AtbZIP60 is the best characterized transcription factor involved in the ER stress response in plants Iwata and Koizumi 2005a;Iwata et al 2009b).…”

mentioning

confidence: 99%

Transcriptomic response of Arabidopsis thaliana to tunicamycin-induced endoplasmic reticulum stress

Iwata

Sakiyama

Lee

et al. 2010

Plant Biotechnology

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Characterization of two homologs of Ire1p, a kinase/endoribonuclease in yeast, in Arabidopsis thaliana

Cited by 64 publications

References 15 publications

Endoplasmic Reticulum Protein Quality Control and Its Relationship to Environmental Stress Responses in Plants

Endoplasmic Reticulum Protein Quality Control and Its Relationship to Environmental Stress Responses in Plants

Heat induces the splicing by IRE1 of a mRNA encoding a transcription factor involved in the unfolded protein response in Arabidopsis

Transcriptomic response of Arabidopsis thaliana to tunicamycin-induced endoplasmic reticulum stress

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