scholarly journals ER stress response, peroxisome proliferation, mitochondrial unfolded protein response and Golgi stress response

IUBMB Life ◽  
2009 ◽  
Vol 61 (9) ◽  
pp. 871-879 ◽  
Author(s):  
Hiderou Yoshida
Keyword(s):  
Stress Response ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Peroxisome Proliferation ◽  
Unfolded Protein ◽  
Er Stress Response ◽  
Protein Response ◽  
Mitochondrial Unfolded Protein Response

scholarly journals HY5, a positive regulator of light signaling, negatively controls the unfolded protein response inArabidopsis

2017 ◽  
Vol 114 (8) ◽  
pp. 2084-2089 ◽  
Author(s):  
Ganesh M. Nawkar ◽  
Chang Ho Kang ◽  
Punyakishore Maibam ◽  
Joung Hun Park ◽  
Young Jun Jung ◽  
...  
Keyword(s):  
Stress Response ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Molecular Mechanism ◽  
26S Proteasome ◽  
Light Signaling ◽  
Unfolded Protein ◽  
Er Stress Response ◽  
The Unfolded Protein Response ◽  
Protein Response

Light influences essentially all aspects of plant growth and development. Integration of light signaling with different stress response results in improvement of plant survival rates in ever changing environmental conditions. Diverse environmental stresses affect the protein-folding capacity of the endoplasmic reticulum (ER), thus evoking ER stress in plants. Consequently, the unfolded protein response (UPR), in which a set of molecular chaperones is expressed, is initiated in the ER to alleviate this stress. Although its underlying molecular mechanism remains unknown, light is believed to be required for the ER stress response. In this study, we demonstrate that increasing light intensity elevates the ER stress sensitivity of plants. Moreover, mutation of the ELONGATED HYPOCOTYL 5 (HY5), a key component of light signaling, leads to tolerance to ER stress. This enhanced tolerance ofhy5plants can be attributed to higher expression of UPR genes. HY5 negatively regulates the UPR by competing with basic leucine zipper 28 (bZIP28) to bind to the G-box–like element present in the ER stress response element (ERSE). Furthermore, we found that HY5 undergoes 26S proteasome-mediated degradation under ER stress conditions. Conclusively, we propose a molecular mechanism of crosstalk between the UPR and light signaling, mediated by HY5, which positively mediates light signaling, but negatively regulates UPR gene expression.

scholarly journals The stress-induced protein NUPR1 orchestrates protein translation during ER-stress by interacting with eIF2α

2020 ◽  
Author(s):  
Maria Teresa Borrello ◽  
Patricia Santofimia-Castaño ◽  
Marco Bocchio ◽  
Angela Listi ◽  
Nicolas Fraunhoffer ◽  
...  
Keyword(s):  
Stress Response ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Protein Translation ◽  
Morphological Observation ◽  
Unfolded Protein ◽  
Er Stress Response ◽  
General Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

AbstractNUPR1 is a stress response protein overexpressed upon cell injury in virtually all organs including the exocrine pancreas. Despite NUPR1’s well established role in the response to cell stress, the molecular and structural machineries triggered by NUPR1 activation remain largely unknown. In this study, we uncover an important role for NUPR1 in participating in the unfolded protein response pathway and the endoplasmic reticulum stress response. Biochemical results, confirmed by ultrastructural morphological observation, revealed alterations in the UPR in acinar cells of germline-deleted NUPR1 murine models, consistent with the inability to restore general protein translation. Bioinformatical analysis of NUPR1 interacting partners showed significant enrichment in translation initiation factors, including eukaryotic initiation factor (eIF) 2α. Co-immunoprecipitation and proximity ligation assays both confirmed interaction between NUPR1 and eIF2α and its phosphorylated form (p-eIF2α). Our. Moreover, our data also suggest loss of NUPR1 in cells results in maintained eIF2α phosphorylation and evaluation of nascent proteins by (peIF2α), and click chemistry revealed that NUPR1-depleted PANC-1 cells displayed a slower post stress protein translational recovery compared to wild-type. Combined, this data proposes a novel role for NUPR1 in the integrated stress response pathway, at least partially through promoting efficient PERK-branch activity and resolution through a unique interaction with eIF2α.SignificanceIn the pancreas, NUPR1 is required for a resolution of the ER stress response. During ER stress response, NUPR1 binds both eIF2α allowing for its dephosphorylation and restoration of new protein synthesis.HighlightsBiochemical analysis revealed a general reduction in the protein expression of downstream mediators of the unfolded protein response in the pancreas of mice lacking Nupr1. This finding suggests a novel role for NUPR1 in the UPR/ER stress response.Ultrastructural analysis of pancreata revealed reduced morphological alterations in tunicamycin-treated Nupr1-/- mice compared to Nupr1+/+ mice consistent with a maintained block in general protein translation.Co-immunoprecipitation of tagged NUPR1 confirmed a novel interaction with eIF2α. Depletion of NUPR1 prolonged phosphorylation of eIF2α, suggesting it may be involved in attenuation of the PERK branch of the UPR.NUPR1-depleted PANC-1 cells displayed a slower recovery of protein translation following UPR activation

scholarly journals Endoplasmic Reticulum Stress-Induced Formation of Transcription Factor Complex ERSF Including NF-Y (CBF) and Activating Transcription Factors 6α and 6β That Activates the Mammalian Unfolded Protein Response

2001 ◽  
Vol 21 (4) ◽  
pp. 1239-1248 ◽  
Author(s):  
Hiderou Yoshida ◽  
Tetsuya Okada ◽  
Kyosuke Haze ◽  
Hideki Yanagi ◽  
Takashi Yura ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Transcription Factors ◽  
Stress Response ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Consensus Sequence ◽  
Unfolded Protein ◽  
Er Stress Response ◽  
Protein Response ◽  
Transcriptional Induction

ABSTRACT The levels of molecular chaperones and folding enzymes in the endoplasmic reticulum (ER) are controlled by a transcriptional induction process termed the unfolded protein response (UPR). The mammalian UPR is mediated by the cis-acting ER stress response element (ERSE), the consensus sequence of which is CCAAT-N9-CCACG. We recently proposed that ER stress response factor (ERSF) binding to ERSE is a heterologous protein complex consisting of the constitutive component NF-Y (CBF) binding to CCAAT and an inducible component binding to CCACG and identified the basic leucine zipper-type transcription factors ATF6α and ATF6β as inducible components of ERSF. ATF6α and ATF6β produced by ER stress-induced proteolysis bind to CCACG only when CCAAT is bound to NF-Y, a heterotrimer consisting of NF-YA, NF-YB, and NF-YC. Interestingly, the NF-Y and ATF6 binding sites must be separated by a spacer of 9 bp. We describe here the basis for this strict requirement by demonstrating that both ATF6α and ATF6β physically interact with NF-Y trimer via direct binding to the NF-YC subunit. ATF6α and ATF6β bind to the ERSE as a homo- or heterodimer. Furthermore, we showed that ERSF including NF-Y and ATF6α and/or β and capable of binding to ERSE is indeed formed when the cellular UPR is activated. We concluded that ATF6 homo- or heterodimers recognize and bind directly to both the DNA and adjacent protein NF-Y and that this complex formation process is essential for transcriptional induction of ER chaperones.

scholarly journals Homolog of ELAC2 is a central regulator of the mitochondrial unfolded protein response

2021 ◽  
Author(s):  
James P Held ◽  
Benjamin R Saunders ◽  
Claudia V Pereria ◽  
Maulik R Patel
Keyword(s):  
Transcription Factors ◽  
Stress Response ◽  
Unfolded Protein Response ◽  
Negative Regulation ◽  
Mitochondrial Stress ◽  
Trna Processing ◽  
Unfolded Protein ◽  
Necessary And Sufficient ◽  
Protein Response ◽  
Mitochondrial Unfolded Protein Response

The mitochondrial unfolded protein response (UPRmt) has emerged as a predominant mechanism that preserves mitochondrial function. Consequently, multiple pathways likely exist to modulate UPRmt. We unexpectedly discovered that the tRNA processing enzyme, homolog of ELAC2 (HOE-1), is central to UPRmt regulation in Caenorhabditis elegans. We find that nuclear HOE-1 is necessary and sufficient to robustly activate UPRmt. We show that HOE-1 acts via transcription factors ATFS-1 and DVE-1 that are crucial for UPRmt. Mechanistically, we show that HOE-1 likely mediates its effects via tRNAs, as blocking tRNA export prevents HOE-1-induced UPRmt. Interestingly, we find that HOE-1 does not act via the integrated stress response, which can be activated by uncharged tRNAs, pointing towards its reliance on a new mechanism. Finally, we show that the subcellular localization of HOE-1 is responsive to mitochondrial stress and is subject to negative regulation via ATFS-1. Together, we have discovered a novel RNA-based cellular pathway that modulates UPRmt.

scholarly journals COPII mitigates ER stress by promoting formation of ER whorls

Cell Research ◽  
2020 ◽  
Author(s):  
Fang Xu ◽  
Wanqing Du ◽  
Qin Zou ◽  
Yuting Wang ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Stress Response ◽  
Er Stress ◽  
Protein Translation ◽  
Unfolded Protein ◽  
Er Stress Response ◽  
Membrane Budding ◽  
Free Environment ◽  
The Unfolded Protein Response ◽  
Protein Response ◽  
Er Whorls

Abstract Cells mitigate ER stress through the unfolded protein response (UPR). Here, we report formation of ER whorls as an effector mechanism of the ER stress response. We found that strong ER stress induces formation of ER whorls, which contain ER-resident proteins such as the Sec61 complex and PKR-like ER kinase (PERK). ER whorl formation is dependent on PERK kinase activity and is mediated by COPII machinery, which facilitates ER membrane budding to form tubular-vesicular ER whorl precursors. ER whorl precursors then go through Sec22b-mediated fusion to form ER whorls. We further show that ER whorls contribute to ER stress-induced translational inhibition by possibly modulating PERK activity and by sequestering translocons in a ribosome-free environment. We propose that formation of ER whorls reflects a new type of ER stress response that controls inhibition of protein translation.

scholarly journals Mitochondrial translation inhibition triggers ATF4 activation, leading to integrated stress response but not to mitochondrial unfolded protein response

2020 ◽  
Vol 40 (11) ◽  
Author(s):  
Katsuhiko Sasaki ◽  
Takeshi Uchiumi ◽  
Takahiro Toshima ◽  
Mikako Yagi ◽  
Yura Do ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Stress Response ◽  
Unfolded Protein Response ◽  
Integrated Stress Response ◽  
Mitochondrial Translation ◽  
Translation Inhibition ◽  
Unfolded Protein ◽  
Protein Response ◽  
Mitochondrial Unfolded Protein Response

Abstract Mitochondrial–nuclear communication, known as retrograde signaling, is important for regulating nuclear gene expression in response to mitochondrial dysfunction. Previously, we have found that p32/C1qbp-deficient mice, which have a mitochondrial translation defect, show endoplasmic reticulum (ER) stress response and integrated stress response (ISR) gene expression in the heart and brain. However, the mechanism by which mitochondrial translation inhibition elicits these responses is not clear. Among the transcription factors that respond to mitochondrial stress, activating transcription factor 4 (ATF4) is a key transcription factor in the ISR. Herein, chloramphenicol (CAP), which inhibits mitochondrial DNA (mtDNA)-encoded protein expression, induced eukaryotic initiation factor 2 α subunit (eIF2α) phosphorylation and ATF4 induction, leading to ISR gene expression. However, the expression of the mitochondrial unfolded protein response (mtUPR) genes, which has been shown in Caenorhabditis elegans, was not induced. Short hairpin RNA-based knockdown of ATF4 markedly inhibited the CAP-induced ISR gene expression. We also observed by ChIP analysis that induced ATF4 bound to the promoter region of several ISR genes, suggesting that mitochondrial translation inhibition induces ISR gene expression through ATF4 activation. In the present study, we showed that mitochondrial translation inhibition induced the ISR through ATF4 activation rather than the mtUPR.

scholarly journals Activation of mitochondrial unfolded protein response protects against multiple exogenous stressors

2021 ◽  
Vol 4 (12) ◽  
pp. e202101182
Author(s):  
Sonja K Soo ◽  
Annika Traa ◽  
Paige D Rudich ◽  
Meeta Mistry ◽  
Jeremy M Van Raamsdonk
Keyword(s):  
Stress Response ◽  
Unfolded Protein Response ◽  
Vital Role ◽  
Antioxidant Genes ◽  
Multiple Stress ◽  
Constitutive Activation ◽  
Unfolded Protein ◽  
Stress Response Pathway ◽  
Protein Response ◽  
Mitochondrial Unfolded Protein Response

The mitochondrial unfolded protein response (mitoUPR) is an evolutionarily conserved pathway that responds to mitochondria insults through transcriptional changes, mediated by the transcription factor ATFS-1/ATF-5, which acts to restore mitochondrial homeostasis. In this work, we characterized the role of ATFS-1 in responding to organismal stress. We found that activation of ATFS-1 is sufficient to cause up-regulation of genes involved in multiple stress response pathways including the DAF-16–mediated stress response pathway, the cytosolic unfolded protein response, the endoplasmic reticulum unfolded protein response, the SKN-1–mediated oxidative stress response pathway, the HIF-1-mediated hypoxia response pathway, the p38-mediated innate immune response pathway, and antioxidant genes. Constitutive activation of ATFS-1 increases resistance to multiple acute exogenous stressors, whereas disruption of atfs-1 decreases stress resistance. Although ATFS-1–dependent genes are up-regulated in multiple long-lived mutants, constitutive activation of ATFS-1 decreases lifespan in wild-type animals. Overall, our work demonstrates that ATFS-1 serves a vital role in organismal survival of acute stressors through its ability to activate multiple stress response pathways but that chronic ATFS-1 activation is detrimental for longevity.

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