BBS4 Is Essential for Nuclear Transport of Transcription Factors Mediating Neuronal ER Stress Response

2020 ◽  
Vol 58 (1) ◽  
pp. 78-91
Author(s):  
Avital Horwitz ◽  
Ruth Birk
Keyword(s):  
Transcription Factors ◽  
Stress Response ◽  
Er Stress ◽  
Nuclear Transport ◽  
Er Stress Response

scholarly journals Transcriptional regulation of mouse mesencephalic astrocyte-derived neurotrophic factor in Neuro2a cells

2013 ◽  
Vol 18 (3) ◽  
Author(s):  
Kentaro Oh-Hashi ◽  
Yoko Hirata ◽  
Kazutoshi Kiuchi
Keyword(s):  
Transcription Factors ◽  
Stress Response ◽  
Er Stress ◽  
Neurotrophic Factor ◽  
Promoter Activity ◽  
Luciferase Reporter ◽  
Mrna Levels ◽  
Er Stress Response ◽  
Neuro2a Cells ◽  
Flanking Region

AbstractMesencephalic astrocyte-derived neurotrophic factor (MANF) is a novel type of trophic factor. Recent studies indicate that the MANF gene is induced in response to endoplasmic reticulum (ER) stress through ER stress response element II (ERSE-II) in its 5′-flanking region. In this study, we evaluated the roles of six ER stress response transcription factors in the regulation of the promoter activities of the mouse MANF gene via ERSE-II using various types of mutant MANF luciferase reporter constructs. Treatment with thapsigargin (Tg) induced MANF mRNA generation in parallel with the elevation of ATF6α, sXBP and Luman mRNA levels in Neuro2a cells. Of the six transcription factors, ATF6β most strongly increased the MANF promoter activity via ERSE-II, while the effects of ATF6β and sXBP1 were moderate. However, overexpression of Luman or OASIS did not enhance ERSE-II-dependent MANF promoter activity in Neuro2a cells. To evaluate the relationships between transcription factors in the regulation of ERSE-II-dependent MANF promoter activity, we transfected two effective transcription factor constructs chosen from ATF6α, ATF6β, uXBP1 and sXBP1 into Neuro2a cells with the MANF reporter construct. The MANF promoter activity induced by co-transfection of ATF6α with ATF6β was significantly lower than that induced by ATF6α alone, while other combinations did not show any effect on the ERSE-II-dependent MANF promoter activity in Neuro2a cells. Our study is the first to show the efficiency of ER stress-related transcription factors for ERSE-II in activating the transcription of the mouse MANF gene in Neuro2a cells.

Abstract 281: Sigma-1 Receptor Dependent Pathway for a Protective Endoplasmic Reticulum Stress Response in Cardiomyocytes

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Shafiul Alam ◽  
A. Wayne Orr ◽  
Christopher B. Pattillo ◽  
Md. Shenuarin Bhuiyan
Keyword(s):  
Stress Response ◽  
Er Stress ◽  
Nuclear Transport ◽  
Neuronal Cell ◽  
Neonatal Rat ◽  
Mouse Heart ◽  
Sigma 1 Receptor ◽  
Er Stress Response ◽  
Chop Expression ◽  
Sigma 1

Rationale: We recently reported that Sigma 1 receptor (Sigmar1) is a molecular chaperone protein highly expressed in the heart. Studies involving different cancer and neuronal cell lines indicated Sigmar1 resides in the mitochondrion-associated ER membrane (MAM). However, the subcellular localization of Sigmar1 and the molecular function in ER-stress remains unknown in cardiomyocytes. Here we describe a function for Sigmar1 as an effector of an adaptive ER stress response. Objective: The objective of this study was to elucidate functional roles of Simgar1 in ER-stress in cardiomyocytes. Methods and Results: Subcellular fractionation of the mouse heart showed extensive localization of Sigmar1 in the MAM and mitochondrial fraction. To define the function in an ER-stress response, we used small interfering RNA-mediated Sigmar1 knockdown and adenovirus-mediated overexpression in cultured neonatal rat ventricular cardiomyocytes. We treated with tunicamycin to induce ER stress. In cardiomyocytes, tunicamycin increased C/EBP-homologous protein (CHOP) expression; Sigmar1 overexpression significantly decreased the CHOP expression. We found that Sigmar1 overexpression was sufficient to activate the nuclear transport of spliced X-box binding protein 1 (Xbp1s) with minimal effects in other adaptive ER stress proteins. Sigmar1 knockdown decreased the nuclear transport of Xbp1s, increased the expression of nuclear CHOP and significantly increased LDH release. We also observed significant Sigmar1 expression dependent increases in mitochondrial respiration in cardiomyocytes under ER stress. Hence, Sigmar1 can function inside the cell during disease remodeling to augment ER function and protect through a mechanism involving regulation of Xbp1s. Conclusions: Sigmar1 is an essential component of the adaptive ER stress response in cardiomyocytes. Sigmar1 can regulate ER-stress induced CHOP expression by activating XBP1s signaling in cardiomyocytes. Therefore, Sigmar1 residing at the ER-mitochondrion interface serves as an important subcellular entity in the regulation of cellular survival by enhancing the stress-response signaling between the ER and mitochondria.

scholarly journals Induction of Endoplasmic Reticulum-induced Stress Genes in Panc-1 Pancreatic Cancer Cells Is Dependent on Sp Proteins

2005 ◽  
Vol 280 (16) ◽  
pp. 16508-16513 ◽  
Author(s):  
Maen Abdelrahim ◽  
Shengxi Liu ◽  
Stephen Safe
Keyword(s):  
Pancreatic Cancer ◽  
Endoplasmic Reticulum ◽  
Transcription Factors ◽  
Stress Response ◽  
Er Stress ◽  
Cancer Cells ◽  
Gene Promoters ◽  
Er Stress Response ◽  
Pancreatic Cancer Cells ◽  
Pharmacologically Active

Endoplasmic reticulum (ER) stress plays a critical role in multiple diseases, and pharmacologically active drugs can induce cell death through ER stress pathways. Stress-induced genes are activated through assembly of transcription factors on ER stress response elements (ERSEs) in target gene promoters. Gel mobility shift and chromatin immunoprecipitation assays have confirmed interactions of NF-Y and YY1 with the distal motifs of the tripartite ERSE from the glucose-related protein 78 (GRP78) gene promoter. The GC-rich nonanucleotide (N9) sequence, which forms the ER stress response binding factor (ERSF) complex binds TFII-I and ATF6; however, we have now shown that in Panc-1 pancreatic cancer cells, this complex also binds Sp1, Sp3, and Sp4 proteins. Sp proteins are constitutively bound to the ERSE; however, activation of GRP78 protein (or reporter gene) by thapsigargin or tunicamycin is inhibited after cotransfection with small inhibitory RNAs for Sp1, Sp3, and Sp4. This study demonstrates that Sp transcription factors are important for stress-induced responses through their binding to ERSEs.

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.

Targeted regulation of lymphocytic ER stress response with an overall immunosuppression to alleviate allograft rejection

Biomaterials ◽  
2021 ◽  
pp. 120757
Author(s):  
Yingying Shi ◽  
Yichao Lu ◽  
Chunqi Zhu ◽  
Zhenyu Luo ◽  
Xiang Li ◽  
...  
Keyword(s):  
Stress Response ◽  
Er Stress ◽  
Allograft Rejection ◽  
Er Stress Response

scholarly journals Highly Specialized Ubiquitin-Like Modifications: Shedding Light into the UFM1 Enigma

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 255
Author(s):  
Katharina F. Witting ◽  
Monique P.C. Mulder
Keyword(s):  
Dna Repair ◽  
Stress Response ◽  
Embryonic Development ◽  
Er Stress ◽  
Unmet Needs ◽  
Biological Function ◽  
Post Translational Modification ◽  
Er Stress Response ◽  
Cellular Events ◽  
Complex Signaling

Post-translational modification with Ubiquitin-like proteins represents a complex signaling language regulating virtually every cellular process. Among these post-translational modifiers is Ubiquitin-fold modifier (UFM1), which is covalently attached to its substrates through the orchestrated action of a dedicated enzymatic cascade. Originally identified to be involved embryonic development, its biological function remains enigmatic. Recent research reveals that UFM1 regulates a variety of cellular events ranging from DNA repair to autophagy and ER stress response implicating its involvement in a variety of diseases. Given the contribution of UFM1 to numerous pathologies, the enzymes of the UFM1 cascade represent attractive targets for pharmacological inhibition. Here we discuss the current understanding of this cryptic post-translational modification especially its contribution to disease as well as expand on the unmet needs of developing chemical and biochemical tools to dissect its role.

Abstract 292: The Role of the ATF6 Branch of the ER Stress Response in the Endocrine Heart

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Erik A Blackwood ◽  
Christopher C Glembotski
Keyword(s):  
Stress Response ◽  
Er Stress ◽  
Knockout Mice ◽  
Ex Vivo ◽  
Proteolytic Cleavage ◽  
Isolated Perfused Heart ◽  
Wild Type ◽  
Atrial Myocytes ◽  
Perfused Heart ◽  
Er Stress Response

Rationale: Atrial natriuretic peptide (ANP) is stored in the heart in large dense core granules of atrial myocytes as a biologically inactive precursor, pro-ANP. Hemodynamic stress and atrial stretch stimulate coordinate secretion and proteolytic cleavage of pro-ANP to its bioactive form, ANP, which promotes renal salt excretion and vasodilation, which, together contribute to decreasing blood pressure. While the ATF6 branch of the ER stress response has been studied in ventricular tissue mouse models of myocardial ischemia and pathological hypertrophy, roles for ATF6 and ER stress on the endocrine function of atrial myocytes have not been studied. Objective/Methods: To address this gap in our knowledge, we knocked down ATF6 in primary cultured neonatal rat atrial myocytes (NRAMs) using a chemical inhibitor of the proteolytic cleavage site enabling ATF6 activation and siRNA and measured ANP expression and secretion basally and in response to alpha- adrenergic agonist stimulation using phenylephrine. We also compared the ANP secretion from wild- type mice and ATF6 knockout mice in an ex vivo Langendorff model of the isolated perfused heart. Results: ATF6 knockdown in NRAMs significantly impaired basal and phenylephrine-stimulated ANP secretion. ATF6 knockout mice displayed lower levels of ANP in atrial tissue at baseline as well as after phenylephrine treatment. Similarly, in the ex vivo isolated perfused heart model, less ANP was detected in effluent of ATF6 knockout hearts compared to wild-type hearts. Conclusions: The ATF6 branch of the ER stress response is necessary for efficient co-secretional processing of pro-ANP to ANP and for agonist-stimulated ANP secretion from atrial myocytes. As ANP is secreted in a regulated manner in response to a stimulus and pro-ANP is synthesized and packaged through the classical secretory pathway, we posit that ATF6 is required for adequate expression, folding, trafficking, processing and secretion of biologically active ANP from the endocrine heart.

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