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1
Griffiths, John Mark Ainsley. "The trinitarian gift unfolded : sacrifice, resurrection, communion." Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/29014/.
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Contentious unresolved philosophical and anthropological questions beset contemporary gift theories. What is the gift? Does it expect, or even preclude, some counter-gift? Should the gift ever be anticipated, celebrated or remembered? Can giver, gift and recipient appear concurrently? Must the gift involve some tangible ‘thing’, or is the best gift objectless? Is actual gift-giving so tainted that the pure gift vaporises into nothing more than a remote ontology, causing unbridgeable separation between the gift-as-practised and the gift-as-it-ought-to-be? In short, is the gift even possible? Such issues pervade scholarly treatments across a wide intellectual landscape, often generating fertile inter-disciplinary crossovers whilst remaining philosophically aporetic. Arguing largely against philosophers Jacques Derrida and Jean-Luc Marion and partially against the empirical gift observations of anthropologist Marcel Mauss, I contend in this thesis that only a theological – specifically trinitarian – reading liberates the gift from the stubborn impasses which non-theological approaches impose. That much has been argued eloquently by theologians already, most eminently John Milbank, yet largely with a philosophical slant. I develop the field by demonstrating that the Scriptures, in dialogue with the wider Christian dogmatic tradition, enrich discussions of the gift, showing how creation, which emerges ex nihilo in Christ, finds its completion in him as creatures observe and receive his own perfect, communicable gift alignment. In the ‘gift-object’ of human flesh, believers rejoicingly discern Christ receiving-in-order-to-give and giving-in-order-to-receive, the very reciprocal giftedness that Adamic humanity spurned. Moreover, the depths of Christ’s crucified self-giving and the heights of resurrectional glory, culminating in the Spirit’s eternal communion, convey sin-bound creatures into the new creation, towards their deified end, through liturgical mediation which reveals true giftedness. The gift is thus no aporetic embarrassment but the means of entry into and – more significantly – the very texture of the new, eucharistic creation.
2
Topping, K. D. "NMR studies of the unfolded stated of lysozyme." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235073.
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Salsas, Escat Ramon. "The role of unfolded states in collagen degradation." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57555.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Computational and Systems Biology Program, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references.
Excessive collagen degradation (collagenolysis) has been implicated in a series of diseases such as tumor metastasis, atherosclerosis and arthritis. There are still several unresolved questions about the mechanism of collagenolysis. First, the prototypical structure of the collagen triple helix does not fit into the active site of collagenases, the enzymes responsible of cleaving collagen. Moreover, the scissile bond that is degraded during collagenolysis is hidden from solvent. Therefore it is widely agreed that collagen unfolding must occur in order for collagenolysis to proceed. Some proposed mechanisms suggest that collagenases actively unfold collagen in order to expose the cleavage site, but no direct evidence of such mechanisms has been provided. Second, while several potential cleavage sites exist in the sequence of collagen, only one is cleaved in triple helical collagen. The hypothesis of this work is that locally unfolded states exist in collagen in the absence of collagenases. They occur as a result of the natural thermal fluctuations in the structure of collagen. Collagenolysis occurs when collagenases bind and cleave these unfolded states. In this work, a combination of computational and experimental methods is presented in order to test this hypothesis. Initially, computational results suggest that locally unfolded states are ubiquitous along the structure of collagen. However, it is shown that not all unfolded states are created equal, and that the precise sequence in the vicinity of the true collagenase cleavage site in type III collagen allows collagen to sample locally unfolded states that are complimentary to the collagenase active site. Therefore, it is hypothesized that cleavage site specificity is encoded in the nature of the unfolded states. Next, it is shown that types I and III collagen can be bound and cleaved at the actual cleavage site by just the catalytic domain of collagenases, a finding in apparent contradiction with previous work in this field. These results are interpreted in light of a novel conformational selection mechanism in which collagenases only cleave locally unfolded, vulnerable states. Finally, based on the new mechanism of collagenolysis presented here, new strategies to regulate collagenolysis are proposed.
by Ramon Salsas Escat.
Ph.D.
4
Sanchez, Puig Nuria. "Biophysical studies on native unfolded and misfolded proteins." Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613772.
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Kwok, Alice. "Unfolded protein responses in models of Motor Neuron Disease." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:2f3efba7-dce1-4521-bda6-4db8ee81094d.
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Motor neuron disorders are a heterogeneous group of diseases characterized by the selective degeneration of motor neurons leading to muscle wasting and atrophy. Amyotrophic Lateral Sclerosis (ALS) is the most common amongst these disorders and is characterized by the selective loss of both upper and lower motor neurons in the brain and spinal cord. 20% of familial cases of ALS are caused by mutations in the Cu, Zn-superoxide dismutase gene (SOD1), a ubiquitously expressed enzyme responsible for scavenging superoxide radicals. The exact mechanisms underlying mutant SOD1-mediated neurotoxicity are unknown. Misfolded mutant SOD1 accumulates in the cytosol and mitochondrial intermembrane space (IMS) indicating the involvement of unfolded protein responses in ALS pathogenesis. Unfolded protein responses (UPRs) are complex signal transduction cascades which detect perturbations in protein folding and couple them to the expression of protein quality control machinery thereby allowing individual compartments to adapt to stress. In the cytosol, this study has shown that HspB8 was upregulated by SOD1 mutants, where it induced the clearance of aggregates by macroautophagy. This is a protective mechanism, as overexpression of HspB8 suppressed mutant-SOD1 mediated toxicity. In contrast, HspB8 mutants were impaired in macroautophagy and are toxic to NSC-34 cells. The mechanisms for the IMS-UPR have not been previously identified. To address this issue, a model for the accumulation of misfolded mutant SOD1 within the IMS was created and candidate proteins involved in protein quality control within the IMS were explored at the transcriptional level and at the level of protein expression. Preliminary results revealed some possible candidates that may have a role in the adaptation to mitochondrial stress. Interestingly, increased mitophagy was also found in IMS-G93A expressing cells, advocating the central role of macroautophagy in eliminating protein aggregates and damaged mitochondria in SOD1-FALS.
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Gianni, Davide. "The role of unfolded protein deposits in cardiac dysfunction." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/7029.
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In this study we investigated the role of unfolded proteins as a toxic insult for cardiomyocytes in idiopathic dilated cardiomyopathy (DCM). We first confirmed the presence of amyloid fibers in DCM cardiomyocytes by histological and ultrastructural analysis, showing their preferentially intracellular distribution. These molecular species seem to coexist with low-complexity β-folded precursors (oligomers) which in our experiments could promote increase of systolic Ca2+ in normal cardiomyocytes and alterations of contractility. Our results suggest that these molecular species trigger the overexpression of UPR components such as GRPs, Chop and Caspase 12. In addition we demonstrated the presence of interactions between presenilins (PS) and Serca2a, suggesting a regulatory role of these Alzheimer’s-related proteins on the Ca2+ pump. The genetic analysis of the presenilin genes in DCM samples identified two undescribed mutations in the promoter of PS1, which appeared to inhibit the expression of the protein. The quantification of the presenilin levels showed a considerable decrease of PS2 associated with an increase of PS1. In order to characterize the protein(s) involved in the aggregasomes, we developed a series of purification protocols, which, unfortunately, did not identify a single protein species. As an alternative approach, we focused on the identification of transcripts differentially expressed in iDCM. Our study introduces an innovative three-group analysis in which we used amyloid samples to eliminate the interference related to the accumulation of unfolded peptides and deriving from the progression of HF. Interestingly we recognized a limited number of iDCM-specific genes, including nestin and DSCR1, which are normally correlated to neural development. In conclusion, our findings open intriguing perspectives to increase our knowledge of the etiology and progression of DCM. However further investigation is required to identify the protein(s) involved in the formation of the aggregasomes and the role of these molecular structures in the etiology of the disease.
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Pashley, Clare Louise. "Characterising the unfolded state of Im7 in non-denaturing conditions." Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.550343.
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An understanding of the structural ensemble of the species present at the commencement of protein folding may help to elucidate the role of the primary amino acid sequence in narrowing the search for the native conformation during protein folding. Characterisation of this species is often difficult since the folded state is the predominantly populated species at equilibrium. In addition to this, the study of disordered proteins suffers from a lack of restraints, since the protein can adopt many different conformations in solution. However, advances in computational methods now make it possible to build an ensemble model of the unfolded state using experimentally measured parameters. Previous work has shown the 87-residue, 4-helix protein, Im7, folds with a three-state mechanism via an on-pathway intermediate. While the transition states and populated intermediate on the folding pathway have been characterised in atomistic detail, knowledge of the unfolded ensemble under the same ambient conditions remained sparse. Although the urea denatured state of Im7 has been characterised, single molecule experiments revealed that this species of Im7 becomes compact upon dilution of the denaturant. These observations suggest that the structural ensemble of the unfolded state of Im7 is different in the absence of urea. In this thesis, destabilising amino acid substitutions were introduced into the sequence of Im7, such that the unfolded state is predominantly populated at equilibrium in the absence of denaturant. Results from far and near-UV CD, fluorescence, urea titration and heteronuclear NMR experiments reveal that three amino acid substitutions (L18A L19A L37A) are sufficient to prevent Im7 folding. Using this variant the unfolded state of Im7 under ambient conditions was then shown to be more compact, and to have increased tendency towards sampling the a-region of Φ/Ψ space compared with the protein in 6 M urea. Measurements of 15N-transverse relaxation rates revealed that sequences corresponding to helical regions in the native protein are conformationally restricted within the unfolded ensemble as a consequence of local hydrophobic clustering without substantial helix formation. By creating hydrophobic deletion mutants and measuring paramagnetic . relaxation effects, possible transient interactions between regions of the sequence relating to the native helix IV and the N-terminal region of the protein were identified, which may restrict conformational sampling within the ensemble. An atomistic model of the unfolded ensemble is then presented to create the first atomistic impression of the unfolded state of Im7. This provides a powerful tool for designing future experiments for refinement of the presented model, and for probing the effect of unfolded state interactions on the folding pathway of Im7.
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Padda, Rajneet. "Regulation of the unfolded protein response by GADD34 and CReP." Scholarly Commons, 2016. https://scholarlycommons.pacific.edu/uop_etds/170.
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The regulation of protein synthesis and protein folding is crucial for normal cell function. The endoplasmic reticulum (ER) has crucial roles in safeguarding the correct folding and assembling of proteins through the use of ER molecular chaperones. Homeostasis disruption of the ER leads to activation of the Unfolded Protein Response. The UPR is a three-arm pathway that plays a role in regulating ER stress and ultimately leads to cell survival or cell death if the cell fails to recover. There are three major proteins for sensing Endoplasmic Reticulum stress: RNA dependent protein kinase RNA like endoplasmic reticulum kinase (PERK), activating transcription factor 6 (ATF6), and inositol-requiring ER-to-nucleus signal kinase 1 (IRE1). PERK activation leads to the phosphorylation of the α-subunit of the translation initiation factor eIF2α on Serine 51 in activating its function. EIF2α phosphorylation leads to up-regulation of GADD34 and GADD34 bind protein phosphatase 1 (PP1) to dephosphorylate eIF2α and brings the cell back into homeostasis. CReP, similar to GADD34, binds to PP1, to dephosphorylate eIF2α. The RVxF motif, RARA sequence, and amino acids throughout the GADD34 sequence play a role in PP1 binding and are essential for dephosphorylating eIF2α in cells. The first 180 amino acids of GADD34 play a role in subcellular localization whereas the first 300 amino acids of CReP play a role for localization to the ER. Early on in the UPR the levels of binding immunoglobulin protein (BiP), CHOP, GADD34, and CReP increase; however, the mRNA levels of CReP drop during the 24-HR Thapsigargin treated stage. Two primary proteins that bind CReP were COPS5 and SNAPIN. Understanding the UPR is important because the inhibiting of GADD34 and CReP have been shown to improve many neurodegenerative diseases.
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Xu, Ping. "Sensing and analyzing unfolded protein response during heterologous protein production :." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 205 p, 2008. http://proquest.umi.com/pqdweb?did=1555621341&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Ghosh, Rajarshi. "Transcriptional Regulation of VEGFA by Unfolded Protein Response Signaling Pathway." eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/469.
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The endoplasmic reticulum is the primary organelle in the cell which has the responsibility of properly folding proteins belonging to the secretory pathway. Secretory proteins are essential for a variety of functions within the body like metabolism, growth and survival. Hence, proper folding of the proteins in the ER is absolutely essential to maintain cellular and body function. The environment of the ER is substantially different from that of the cytoplasm and is primed essentially to provide the optimum conditions to fold newly synthesized polypeptides following translation by the ribosomes in the cytoplasm and on the surface of the ER.
In order for secretory proteins to fold properly, ER homeostasis must be maintained. ER homeostasis is defined by the dynamic balance between the ER protein load and the ER capacity to process this load. The optimum environment of the ER, or ER homeostasis, can be perturbed by pathological processes such as hypoxia, glucose deprivation, viral infections, environmental toxins, inflammatory cytokines, and mutant protein expression, as well as by physiological processes such as aging. Disruption of ER homeostasis causes accumulation of unfolded and misfolded proteins in the ER. This condition is referred to as ER stress. Cells cope with ER stress by activating the unfolded protein response (UPR).
The UPR is initiated by three ER transmembrane proteins: Inositol requiring 1 (IRE1), PKR-like ER kinase, and activating transcription factor 6 (ATF6). These three master regulators sense and interpret protein folding conditions in the ER and translate this information across the ER membrane to activate downstream effectors, spliced XBP1, phosphorylated eIF2α and ATF4, and cleaved active ATF6 respectively. These effectors have two distinct outputs, homeostatic and apoptotic. Homeostatic outputs are adaptive responses that function to attenuate ER stress and restore ER homeostasis. These responses include the attenuation of protein translation to reduce ER workload and prevent further accumulation of unfolded proteins, upregulation of molecular chaperones and protein processing enzymes to enhance the ER folding activity, and the increase in ER-associated degradation (ERAD) components to promote clearance of unfolded proteins. When ER stress reaches a point where the cells cannot tolerate the load of unfolded proteins any more, apoptosis sets in.
One of the major secretory proteins in mammals, vascular endothelial growth factor VEGF, is essential for either normal or pathological angiogenesis (blood vessel development). VEGFA is the primary member of this family which is expressed in all endothelial cells and is responsible for sprouting and invasion of blood vessels into the interstitium and thus helps in supplying nutrients and oxygen to growing cells. Recent studies have indicated that cells suffering from insufficient blood supply experience ER stress. The ER needs energy and oxygen for the folding process, thus nutrient deprivation (low ATP production) and hypoxia caused by insufficient blood supply leads to inefficient protein folding and ER stress in cells, especially in cancer cells that grow and spread rapidly. This condition also occurs in the development of the mammalian placenta. The placenta is an essential tissue characterized by a lot of blood vessels. It is responsible for the exchange of nutrients and growth factors between maternal and fetal blood vessels and hence is essential for survival of the embryo. Nutrient deprivation and hypoxia stimulate the production of VEGFA and other angiogenic factors, leading to protection against ischaemic injury in both cancer cells as well as the developing placenta.
In this dissertation, we report that the three master regulators of the UPR, IRE1α, PERK and ATF6α, mediate transcriptional regulation of VEGFA under ER stress in cancer cells. Inactivation of any of the three master regulators leads to attenuation of VEGFA expression under ER stress. We show that IRE1α is able to regulate VEGFA through its downstream transcription factor XBP1 which activates the VEGFA promoter. IRE1α mediated VEGFA regulation is also essential for normal development of labyrinthine trophoblast cells in the placenta. ATF6α also regulates VEGFA via its promoter. PERK is able to activate VEGFA by preferential activation of its downstream effector, ATF4, which binds intron 1 of the VEGFA gene. Thus our work reveals a twopronged differential regulatory action of the UPR sensors on VEGFA gene expression.
This work suggests that a fully active UPR is essential for VEGFA upregulation under ER stress. All three regulators are required in cancer cells for normal VEGFA expression. This tight regulation of VEGFA by the UPR presents a wonderful opportunity for therapeutic intervention into angiogenic growth of tumors.
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Mahmood, Ahsan. "Role of SLMAP in Endoplasmic Reticulum Stress and Unfolded Protein Response." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24399.
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Cardiac function is regulated by the molecular components of the sarco/endoplasmic reticulum (ER/SR). Disruptions in homeostatic balance of these proteins and calcium regulation results in activation of ER stress response. Sarcolemmal membrane-associated proteins (SLMAPs) are found in cell membrane, SR/ER, and mitochondria. Overexpression of SLMAP in the myocardium has shown to impair excitation-contraction (E-C) coupling in the transgenic (Tg) mice. ER stress response was examined in Tg mice overexpressing SLMAP in the myocardium. In Tg hearts, changes observed in the expression of proteins involved in ER stress were dependent on the age and sex. SLMAP overexpression results in maladaptive ER stress response, as the mice age. Neonatal cardiomyocytes isolated from the Tg hearts showed decreased viability, upregulation of ER stress response proteins, which were sensitized to thapsigargin-induced stress, and desensitized to palmitate-induced oxidative stress. These findings suggest that normal SLMAP levels are important for proper cardiac function, and cell viability.
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Truong, TrungDung. "Generating Unfolded Views of Tracts by Cutting and Deforming Medical CT Data." INTELLIGENT MEDIA INTEGRATION NAGOYA UNIVERSITY / COE, 2005. http://hdl.handle.net/2237/10394.
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Lemin, Andrew James. "The unfolded protein response and HLA-B27 misfolding : implications for ankylosing spondylitis." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/797/.
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The unfolded protein response (UPR) detects the presence of misfolded proteins in the endoplasmic reticulum (ER) and subsequently relieves ER stress by increasing the folding capacity of the ER. The secretory pathway substrate HLA-B27 is highly associated with the chronic inflammatory disease ankylosing spondylitis (AS) and has a tendency to misfold in the ER. Here, we show that overexpression of HLA-B27 and non-disease associated HLA-B7 in immortalised cell lines leads to heavy chain misoxidation, which is accompanied by upregulation of BiP and splicing of XBP1, a key step in the IRE1 pathway of the UPR which is increasingly being linked with intestinal inflammation. We also demonstrate that different cell lines respond to different ER stress stimuli in distinct ways. We establish that HT1080 cells inefficiently induce a UPR in response to tunicamycin and that this has consequences for cell survival. However, inefficient activation of the UPR in HT1080 cells can be overcome by secondary signals, since co-administration of the tyrosine kinase inhibitor genistein leads to activation of XBP1. Furthermore, we show that genistein can inhibit UPR induction of BiP in response to a range of ER stresses indicating that the cancer drug genistein can inhibit or activate the UPR depending on the environment and cell type. This has implications for inflammatory disease since regulation of the UPR is important in determining a cell’s tendency towards apoptosis.
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Halliday, Mark. "Targeting the unfolded protein response as a potential therapeutic in prion disease." Thesis, University of Leicester, 2014. http://hdl.handle.net/2381/28603.
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Many neurodegenerative disorders, including Alzheimer's (AD), Parkinson's (PD) and prion diseases, are associated with the accumulation of misfolded disease-specific proteins. During prion disease, an increase in misfolded prion protein (PrP) generated by prion replication leads to sustained overactivation of the branch of the unfolded protein response (UPR) that controls the initiation of protein synthesis. The UPR is a protective cellular mechanism that is induced during periods of cellular and endoplasmic reticulum stress. UPR activation aims to restore protein homeostasis, by reducing protein translation, and up-regulating chaperone proteins that assist with proper protein folding. However, sustained activation of this pathway results in persistent repression of translation, resulting in the loss of critical proteins that leads to synaptic failure and neuronal death. Inhibiting the UPR by genetic means has recently been shown to be neuroprotective in prion disease (Moreno et al., 2012). A drug screen was performed in the model organism C. elegans to search for inhibitors of the UPR. 34 compounds were identified, of which five were selected for further analysis in C. elegans before being tested as a potential treatment in prion diseased mice. Two compounds, dibenzoylmethane and trazodone hydrochloride displayed efficacy against prion disease, and represent novel therapeutic targets. GSK2606414, a specific inhibitor of PERK (protein kinase RNA-like endoplasmic reticulum kinase), a key mediator of the UPR induced translational repression was also tested in prion diseased mice. It restored protein synthesis and prevented the development of clinical prion disease. These data validate the UPR as a viable target in prion disease, and uncover promising potential therapeutics.
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Chawla, Aditi. "Regulation of Ire1 kinase and nuclease activity during the unfolded protein response." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3320634.
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Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed September 24, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Burkart, Alison M. "Energy Metabolism and the Induction of the Unfolded Protein Response: A Dissertation." eScholarship@UMMS, 2010. https://escholarship.umassmed.edu/gsbs_diss/502.
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White adipose plays a major role in the regulation of whole body metabolism through the storage and hydrolysis of triglycerides and by secretion of adipokines. The function of endocrine cells is highly dependent on the unfolded protein response (UPR), a homeostatic signaling mechanism that balances the protein folding capacity of the endoplasmic reticulum (ER) with the cell's secretory protein load. Here we demonstrate that the adipocyte UPR pathway is necessary for its secretory functions, and can thus play a crucial role in the control of whole body energy homeostasis. ER protein folding capacity is dependent both on the number of available chaperones as well as on their activity, which requires a sufficient ATP supply. In 3T3-L1 adipocytes, mitochondrial biogenesis occurred in parallel with induction of the UPR; therefore, we tested whether it was necessary for efficient ER function. Inhibition of mitochondrial ATP synthesis through depletion of Tfam, a mitochondrial transcription factor, or treatment with inhibitors of oxidative phosphorylation, demonstrate that ER function is sensitive to acute changes in adenine nucleotide levels. In addition, adenylate kinase 2 (AK2), which regulates mitochondrial adenine nucleotide interconversion, is markedly induced during adipocyte and B cell differentiation. AK2 depletion impairs induction of the UPR and secretion in both cell types. Interestingly, cytosolic adenylate kinase 1 (AK1) does not have the same effect upon UPR induction. We show that adenine nucleotides promote proper ER function and alterations in specific aspects of ATP synthesis can impair UPR signaling. Understanding the complex energetic regulation of the UPR may provide insight into the relationship between UPR and disease.
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Arensdorf, Angela Marie. "The Mechanisms and Consequences of Gene Suppression During the Unfolded Protein Response." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/4816.
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The endoplasmic reticulum (ER) facilitates the synthesis, assembly and quality control of all secretory, transmembrane, and resident proteins of the endomembrane system. An accumulation of unfolded proteins or a disruption in the specialized folding environment within the organelle causes ER stress, thus impairing the folding capacity of the ER. In response to this stress, the ER initiates a signaling cascade called the unfolded protein response (UPR) in an attempt to restore ER homeostasis.
The vertebrate UPR is propagated by three ER-resident transmembrane proteins (i.e., PERK, IRE1α, and ATF6α), each initiating a signaling cascade that ultimately culminates in production of a transcriptional activator. The UPR was originally characterized as a pathway for the upregulation of ER chaperones, and a comprehensive body of subsequent work has shown that protein synthesis, folding, oxidation, trafficking, and degradation are all transcriptionally enhanced by the UPR. However, UPR activation is also accompanied by extensive mRNA suppression. The mechanisms responsible for this suppression and its consequences for physiological processes beyond the realm of ER protein folding and processing are only now beginning to be described.
The overall goal of my thesis work was to explore this process of UPR-mediated gene suppression by identifying the mechanisms involved and the cellular processes affected. As a result, I characterized a novel mechanism of UPR-mediated transcriptional repression involving the translational regulation of the transcription factor C/EBPβ resulting in the suppression of the gene Il4ra, encoding an essential subunit of the IL-4/IL-13 receptor. As a consequence of this suppression, a novel effect of ER stress was identified in the impairment of IL-4/IL-13 signaling, a finding of potential significance in the study of inflammatory disease. In addition to this mechanism, I validated a novel approach to the identification of UPR-regulated transcription factors using publically available bioinformatic software. Through this analysis, I identified the transcription factor HNF4α as a novel post-translational UPR-regulated transcription factor, the regulation of which, resulted in the suppression of a number of lipid metabolic genes. This analysis not only identified a novel UPR-regulated transcription factor, but also presented a new tool for the characterization of UPR-mediated gene suppression.
My work represents an independent and original investigation into the process of UPR-mediated gene suppression; and reveals that the UPR facilitates transcriptional suppression through the transcriptional, translational, and post-translational regulation of multiple transcription factors, resulting in the coordinated attenuation of physiological pathways. This function of the UPR is likely to contribute to metabolic, inflammatory, and other chronic disease states.
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TOZZI, ALESSANDRA. "The unfolded protein response: a link between endometrioid ovarian carcinoma and endometriosis." Doctoral thesis, Università Politecnica delle Marche, 2017. http://hdl.handle.net/11566/245358.
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Lo scopo del seguente lavoro è di analizzare il profilo di attivazione dei geni legati al pathway dell’Unfolded Protein Response (UPR) nel carcinoma endometrioide dell’ovaio e di valutare il suo possibile coinvolgimento nella trasformazione neoplastica dell’endometriosi.
Lo studio è stato eseguito utilizzando diversi campioni istologici: carcinoma endometrioide dell’ovaio, tessuto ovarico sano, cisti endometriosica, endometrio eutopico provenienti da pazienti con endometriosi e da pazienti con endometrio sano. Da tutti i campioni è stato estratto l’RNA e sintetizzato il cDNA utilizzando la trascrizione inversa. Il cDNA è stato utilizzato per i saggi di espressione quantitativa dei geni, tramite Real Time PCR, con analisi dei geni appartenenti al pathway dell’UPR. I campioni sono stati divisi in tre gruppi: patienti con endometriosi (n=6), pazienti sane (n=6) e pazienti con carcinoma endometrioide dell’ovaio (n=6).
L’analisi statistica effettuata è il t-test, con analisi delle differenze statistiche tra i dati provenienti da pazienti sane (CTRL) e pazienti affette da endometriosi (Ectopic e Eutopic) e pazienti affette da carcinoma endometrioide dell’ovaio (CA).
Abbiamo in primo luogo analizzato la differente espressione del pathway dell’UPR nel carcinoma endometrioide dell’ovaio, comparandolo al tessuto ovarico sano e abbiamo dimostrato un’alterata espressione dei geni dell’UPR nelle pazienti tumorali. In secondo luogo, abbiamo analizzato l’espressione genica dell’UPR nel carcionma endometrioide ovarico, comparandola all’endometrio sano di pazienti sane e di pazienti affette da endometriosi.
Il nostro studio mostra una graduale riduzione dell’espressione del gene XBP1 nell’endometriosi, caratterizzata da intensa infiammazione e nel carcinoma endometrioide dell’ovaio, valorizzando l’ipotesi che XBP1 possa rappresentare un marker di trasformazione neoplastica.
In conclusione XBP1 ha un’alta espressione nell’endometrio sano, un tessuto costitutivamente secretivo, e poi gradualmente riduce la sua espressione nell’endometriosi e, in maniera più accentuata, nel carcinoma ovarico.
Comprendere questi meccanismi potrebbe rappresentare uno step importante per una migliore definizione della patogenesi tumorale e per lo sviluppo in futuro di terapie geniche mirate.The present study aims to analyze the activation profile of Unfolded Protein Response (UPR) related genes in endometriod ovarian carcinoma and to assess its possible involvement in the neoplastic transformation from endometriosis. The study was performed using different histological samples: endometrioid carcinoma of the ovary, healthy ovary, endometriosis cysts, eutopic endometrium from patients with endometriosis and healthy endometrium. From all the samples RNA was extracted and cDNA synthesis was performed by reverse transcription. cDNA was used for quantitative gene expression assays, made by Real Time PCR, analyzing genes belonging to the UPR pathway. Samples were divided into three groups: patients with endometriosis (n = 6), healthy patients (n = 6) patients with ovarian endometrioid carcinoma (n = 6). Statistical analysis performed was a t - test, testing the statistical differences, between data means from healthy patients (CTRL) and groups of patients with endometriosis (Ectopic and Eutopic) and patient with endometrioid carcinoma of the ovary (CA). We started analyzing the different expression of UPR pathway in endometrioid ovarian carcinoma compared to healthy ovary and we demonstrated an altered UPR gene expression in patients affected by endometrioid ovarian carcinoma, compared to healthy ovary. As a second step, we decided to analyze the UPR pathway genetic expression in the endometrioid ovarian carcinoma compared to the endometrium of healthy patients and of endometriosis patients. Our study shows a gradual reduction of XBP1 expression in endometriosis, characterized by intense inflammation, and endometrioid ovarian carcinoma, thus strengthening the hypothesis of XBP1 as a marker of neoplastic transformation. Conclusively XBP1s has a high basic expression in healthy endometrium, being a secretive tissue, then gradually decreases in endometriosis and to a higher degree, in ovarian carcinoma. Understanding these mechanisms could represent an important step, for a better definition of cancer pathogenesis, and also in the future, for the development of customized therapies.
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Hagarman, Andrew Michael Schweitzer-Stenner Reinhard. "Conformations of unfolded and partially folded peptides and proteins probed by optical spectroscopy /." Philadelphia, Pa. : Drexel University, 2010. http://hdl.handle.net/1860/3313.
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Hou, Shangming. "In vivo activation of the endoplasmic reticulum unfolded protein response without disturbed proteostasis." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46514.
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The Mediator is a conserved transcriptional co-factor complex required for eukaryotic gene expression. In C. elegans, the Mediator subunit mdt-15 is essential for the expression of genes involved in fatty acid metabolism and ingestion-associated stress response. mdt-15 loss-of-function causes defects in reproduction and mobility and shortens lifespan. In the present study, we find that mdt-15 depletion or mutation specifically decreases membrane phospholipid unsaturation. Accordingly, mdt-15 worms exhibit disturbed ER homeostasis indicated by a constitutively activated ER unfolded protein response (UPRER). This stress response is only partially the consequence of reduced membrane lipid unsaturation, implicating other mdt-15–regulated processes in the protection against ER stress. Interestingly, mdt-15 inactivation or depletion of lipid metabolism enzymes SCD or sams-1 activates the UPRER without promoting misfolded protein aggregates in the ER. Moreover, these worms all exhibit wild-type sensitivity to chemically induced protein misfolding, and they do not display synthetic lethality with ire-1, whose inactivation causes protein misfolding. Therefore, the constitutive UPRER in mdt-15, SCD, or sams-1 worms is not the consequence of disturbed proteostasis, but likely the direct result from altered properties of the ER membrane. Altogether, our data suggest that the UPRER can be directly induced by membrane disequilibrium and thus acts as a circuit that comprehensively monitors ER homeostasis.
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VanBennekom, Neyda. "Cholera toxin activates the unfolded protein response through an adenylate cyclase-independent mechanism." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5880.
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Cholera toxin (CT) is a bacterial protein toxin responsible for the gastrointestinal disease known as cholera. CT stimulates its own entry into intestinal cells after binding to cell surface receptors. Once internalized, CT is delivered via vesicle-mediated transport to the endoplasmic reticulum (ER), where the CTA1 subunit dissociates from the rest of the toxin and is exported (or translocated) into the cytosol. CTA1 translocates from the ER lumen into the host cytosol by exploiting a host quality control mechanism called ER-associated degradation (ERAD) that facilitates the translocation of misfolded proteins into the cytosol for degradation. Cytosolic CTA1, however, escapes this fate and is then free to activate its target, heterotrimeric G-protein subunit alpha (Gs?), leading to adenlyate cyclase (AC) hyperactivation and increased cAMP concentrations. This causes the secretion of chloride ions and water into the intestinal lumen. The result is severe diarrhea and dehydration which are the major symptoms of cholera. CTA1's ability to exploit vesicle-mediated transport and ERAD for cytosolic entry demonstrates a potential link between cholera intoxication and a separate quality control mechanism called the unfolded protein response (UPR), which up-regulates vesicle-mediated transport and ERAD during ER stress. Other toxins in the same family such as ricin and Shiga toxin were shown to regulate the UPR, resulting in enhanced intoxication. Here, we show UPR activation by CT, which coincides with a marked increase in cytosolic CTA1 after 4 hours of toxin exposure. Drug induced-UPR activation also increases CTA1 delivery to the cytosol and increases cAMP concentrations during intoxication. We investigated whether CT stimulated UPR activation through Gs? or AC. Chemical activation of Gs? induced the UPR and increased CTA1 delivery to the cytosol. However, AC activation did not increase cytosolic CTA1 nor did it activate the UPR. These data provide further insight into the molecular mechanisms that cause cholera intoxication and suggest a novel role for Gs? during intoxication, which is UPR activation via an AC-independent mechanism.M.S.
Masters
Molecular Biology and Microbiology
Medicine
Molecular and Microbiology
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Madadi, Linsey Ida. "Targeting the unfolded protein response as a novel therapeutic approach in haematological malignancies." Thesis, Queen Mary, University of London, 2012. http://qmro.qmul.ac.uk/xmlui/handle/123456789/8534.
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The unfolded protein response (UPR) is a complex signalling pathway activated in response to endoplasmic reticulum stress. In recent years, the UPR has been implicated in cancer and chemosensitivity, particularly in solid tumours. This thesis investigated the potential value of targeting the UPR as a novel therapeutic approach in haematological malignancies using a panel of cell lines representing AML, lymphoma and myeloma. The UPR was constitutively active in these haematological cancer cell lines, with differential activation of key UPR proteins both in the panel and between the panel, peripheral blood mononuclear cells and the colorectal cancer cell line HT-29. A number of strategies were used to modulate the UPR and study chemosensitivity. Minimally toxic concentrations of the ER stress inducer thapsigargin protected cells from cytotoxic agents, with a reduction in antiproliferative drug effect. The activity of the novel small molecule versipelostatin, reported to downregulate the ER molecular chaperones GRP78 and GRP94, was also investigated, with the downregulation previously reported in solid tumour cell lines (Park et al. 2004) confirmed in HT-29 cells, but not observed in the haematological cell lines studied (although versipelostatin was an effective cytotoxic agent at low micromolar concentration). Combination experiments with the chemical chaperone 4-phenylbutyric acid (PBA) resulted in a small increase in apoptosis when PBA was combined with ER stress inducers. However, PBA also showed HDAC inhibitory activity at the concentrations used. Finally, siRNA mediated silencing of GRP78 and GRP94 in THP1 (AML) and U266 (myeloma) cells resulted in a decrease in the targeted protein, but showed only minimal effects on chemosensitivity. In conclusion, the UPR is activated in these haematological cancer cell lines and plays a complex role in chemosensitivity. In contrast to previous reports in solid tumour cells, modulating the UPR in these haematological malignancies had only a modest effect on chemosensitivity.
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Wang, Chi-Fong. "Genetic analysis of the unfolded protein response in Caenorhabditis elegans physiology and immunity." Thesis, Boston University, 2012. https://hdl.handle.net/2144/12667.
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Thesis (M.A.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.Protein folding is a fundamental function of the cell, and chaperone proteins are essential to ensure the quality of secretory and membrane-bound proteins leaving the endoplasmic reticulum (ER). In eukaryotic cells, an increase in translational load that exceeds the capacity of chaperone proteins results in the accumulation of misfolded proteins in the ER, a condition termed ER stress. A network of signaling pathways, known as the Unfolded Protein Response (UPR), senses and responds to ER stress by globally decreasing translational load, specifically increasing expression of chaperone proteins, and expanding the ER lumen. In metazoans the UPR is mediated through three signaling pathways: IRE-1, PEK-1, and ATF-6. The IRE-1 branch of the UPR is highly conserved and found in all eukaryotic cells, from yeast to mammals. Previous work has shown that XBP-1, a transcription factor activated by IRE-1, plays a critical role in the survival of Caenorhabditis elegans worms on pathogenic Pseudomonas aeruginosa bacteria by protecting the animal from excessive ER stress induced by immune activation (Richardson et al., 2010). XBP-1 also contributes to the maintenance of ER homeostasis, as mutant worms lacking XBP-1 exhibit constitutively elevated ER stress (Richardson et al., 2011). Our goal was to explore and identify novel genes that interact with the IRE-1/XBP-1 branch of the UPR. This was done by studying worms lacking XBP-1 and possessing mutations that suppressed immune-induced larval lethality and other XBP-1 loss-of-function phenotypes, presumably through some compensatory mechanism(s). ER stress was induced by four distinct methods (growth on pathogenic bacteria, tunicamycin treatment, heat stress, and removal of the PEK-1 branch of the UPR). This study yielded promising preliminary results for the regulation of XBP-1. The tunicamycin treatment identified probable suppressors of basal ER stress specifically, not just immune-induced lethality. The heat-stress results support a correlation between temperature and UPR induction, a relationship which currently remains unclear. Our data also suggest that PEK-1 has a compensatory role in the absence of XBP-1, although this awaits confirmation that it is independent of functional RNAi machinery. More work is needed to identify the genes responsible for alleviating ER stress and to further understand the complex regulation of the UPR.
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Rath, Eva [Verfasser]. "Mitochondrial unfolded protein response in the epithelium: relevance to intestinal inflammation / Eva Rath." München : Verlag Dr. Hut, 2012. http://d-nb.info/1021072850/34.
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Marcilla, Etxenike Amaia. "The Two Faces of Janus: Unfolded Protein Response - Autophagy in Cell Death and Survival." Doctoral thesis, Universitat de les Illes Balears, 2012. http://hdl.handle.net/10803/97299.
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En esta tesis se estudian los efectos farmacológicos de derivados lipídicos frente el glioma y el Alzheimer. Los beneficios de este tipo de fármacos, basados en la terapia lipídica de membrana, están asociados con la modulación de la composición y las propiedades fisicoquímicas de membrana. En concreto, el ácido 2-hidroxioleico (2OHOA) es un potente fármaco antitumoral que fue diseñado para regular la composición y la estructura de la membrana lipídica así como la función de importantes proteínas de membrana. Por otro lado, el ácido 2-hidroxiaraquidónico (2OHARA), el ácido 2-hidroxieicosapentaenóico (2OHEPA), y el ácido 2-hidroxidocosahexanóico (2OHDHA) son derivados lipídicos hidroxilados que fueron diseñados en nuestro grupo de investigación para el tratamiento del Alzheimer. Este trabajo se ha basado en el estudio del funcionamiento de estos derivados de ácidos grasos hidroxilados en la modulación de las vías de señalización de la UPR (respuesta a las proteínas mal plegadas) y de la autofagia en células de glioma y células neuronales.In this thesis, the pharmacological effects of lipid derivatives against glioma and Alzheimer's Disease are studied. The benefits of this type of drugs, which are based on the lipid membrane therapy, are associated with the modulation of the composition and physicochemical properties of membranes. 2-Hydroxyoleic acid (2OHOA) is a potent antitumor drug designed to regulate membrane lipid composition and structure and the function of important membrane proteins. In addition, 2- hydroxyarachidonic acid (2OHARA; LP204A1), 2-hydroxyeicosapentaenoic acid (2OHEPA; LP205A1), and 2-hydroxydocosahexanoic acid (2OHDHA; LP226A1) are new hydroxy derivated lipids designed in our group for the treatment of Alzheimer’s Disease. The main goal of this work was to study how these synthetic hydroxy derivates modulate the unfolded protein response and the autophagy pathways in glioma cells and neuron-like cells for Alzheimer’s Disease.
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Lee, Sarah Angeline. "Curcumin Protects against Renal Ischemia by Activating the Unfolded Protein Response and Inducing HSP70." Yale University, 2009. http://ymtdl.med.yale.edu/theses/available/etd-04062009-215154/.
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The purpose of this study was to establish whether curcumin protects renal proximal tubule cells against ischemic injury, determine whether this postulated cytoprotective effect is mediated through the upregulation of HSP70, and investigate whether the mechanism by which curcumin induces HSP70 expression and confers its protective effect is through activation of the Unfolded Protein Response. LLC-PK1 cells were cultured on collagen-coated filters to mimic conditions of in vivo renal proximal tubule cells and induce cell polarization. Injury with and without curcumin treatment was studied by using chemically-induced ATP-depletion which mimics renal ischemic injury. Cell injury was assessed using a TUNEL assay in order to evaluate DNA cleavage associated with ischemia-induced apoptosis and actin staining used to assess cytoskeletal disruption. Renal ischemic damage was further investigated by determining detachment of the Na-K ATPase from the basolateral membrane, which represents loss of cell polarity. Cells were incubated with curcumin in a dose- and time-response fashion and subsequent levels of HSP70 expression were assessed. Cells were then incubated with AEBSF, an inhibitor of the Unfolded Protein Response (UPR) and HSP70 and BiP/GRP78 (an ER resident chaperone that is upregulated by the UPR) expression levels were evaluated. Results demonstrated that treatment with curcumin during two hours of injury results in significantly less injury-related apoptosis and cytoskeletal disruption compared to control injured cells. It was demonstrated that curcumin induces HSP70 in both a dose- and time-response fashion. Moreover, curcumin treatment resulted in profound stabilization of Na-K ATPase on the basolateral membranes as there was significantly less Na-K ATPase detachment in cells treated with curcumin during two hours of injury compared to control injured cells. Finally, treatment with AEBSF inhibited HSP70 upregulation in curcumin-treated cells as well as inhibiting the GRP78 over-expression otherwise demonstrated in curcumin-treated cells. Protection of proximal tubule cells against renal ischemic injury by curcumin was therefore indicated to be mediated by the activation of the UPR through which HSP70 is upregulated. Curcumins activation of the UPR and induction of HSP70 explains the stabilization of Na-K ATPase on the cytoskeleton and also provides a potential mechanism explaining many of curcumins therapeutic and protective qualities.
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Liao, Nan. "The unfolded protein response increases production of pro-angiogenic factors by tumor cell lines." View the abstract Download the full-text PDF version (on campus access only), 2008. http://etd.utmem.edu/ABSTRACTS/2008-008-Liao-index.html.
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Thesis (M.S. )--University of Tennessee Health Science Center, 2008.Title from title page screen (viewed on July 17, 2008). Research advisor: Linda M. Hendershot, Ph.D. Document formatted into pages (x, 57 p. : ill.). Vita. Abstract. Includes bibliographical references (p. 47-57).
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Stahl, Sebastian [Verfasser], and Wolfram [Akademischer Betreuer] Brune. "Modulation der Unfolded Protein Response durch das murine Cytomegalovirus / Sebastian Stahl. Betreuer: Wolfram Brune." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1034953540/34.
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Choi, Chong Su [Verfasser], and Walter [Akademischer Betreuer] Neupert. "Die mitochondriale Unfolded Protein Response in Saccharomyces cerevisiae / Chong Su Choi ; Betreuer: Walter Neupert." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2019. http://d-nb.info/1184793891/34.
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Lai, Wai-lung, and 黎威龍. "The role of unfolded protein response in the cytotoxicity mechanism ofN-(4-hydroxyphenyl)retinamide." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B39793928.
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Soni, Himanshu [Verfasser], and Karsten [Akademischer Betreuer] Rippe. "Deciphering Potential Role of Unfolded Protein Response in Glioblastoma / Himanshu Soni ; Betreuer: Karsten Rippe." Heidelberg : Universitätsbibliothek Heidelberg, 2019. http://d-nb.info/1196794537/34.
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Richardson, Claire E. "Investigating the role of the Caenorhabditis elegans unfolded protein response in immunity and development." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/70393.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, February 2012.Cataloged from PDF version of thesis.
Includes bibliographical references.
Proteins destined for the secretory pathway are folded, posttranslationally modified, and assembled into complexes in the endoplasmic reticulum (ER). To maintain ER proteostasis, the rate of nascent peptide influx into the ER must be matched with the rate of protein folding and export. An imbalance between peptide influx and ER folding capacity activates a conserved set of signal transduction pathways termed the ER Unfolded Protein Response (UPR), which function to restore ER proteostasis. In metazoans, the UPR is controlled by three signaling pathways, controlled by the ER localized transmembrane sensors IRE-1, PERK/PEK-1, and ATF6/ATF-6. The molecular mechanisms and output of the UPR have been defined largely by exogenously inhibiting ER protein folding, either chemically or through overexpression of unfoldable mutant ER proteins, while genetic studies have implicated essential functions for UPR signaling in normal development and in the pathogenesis of disease. This work defines an essential role for the UPR in Caenorhabditis elegans in protection against host immunity and maintenance of ER proteostasis during development. In Chapter Two, I show that the IRE-1 -XBP- 1 pathway is activated by infection with the bacterial pathogen Pseudomonas aeruginosa and is essential for larval development in the presence of pathogen. Through genetic analyses, I demonstrate that immune activation is necessary and sufficient to activate the IRE-1 -XBP- 1 pathway, and that the function of the IRE-1 -XBP- 1 pathway during infection is to protect against the host immune response. In Chapter Three, I present evidence suggesting that the IRE-1 and PEK- 1 negative feedback loops function constitutively to maintain ER proteostasis, even during growth under standard, "unstressed" conditions. Together, these studies highlight the integral role of UPR signaling in C. elegans physiology, and future work, described in Chapters Four and Five, will use genetic approaches to further define the molecular mechanisms underlying this requirement for UPR activity.
by Claire E. Richardson.
Ph.D.
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Duarte, Daniel Fernandes. "Structural characterization of the urea-unfolded state of Colicin Immunity Protein Im7 and Im9." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10387.
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Dissertação para obtenção do Grau de Mestre em
Bioquímica Estrutural e FuncionalMost single domain proteins have the ability to fold spontaneously into a precise, functional three-dimensional structure in seconds or less. Understanding how this transition occurs will not only help to uncover the way in which an amino acid sequence encodes the corresponding structure but is also likely to provide insight into the folding/unfolding transitions that many proteins undergo as part of their normal functioning. The characterization of these states is particularly important because they often play crucial roles in folding and misfolding processes, responsible for many human neurodegenerative diseases, such as Alzheimer’s and Parkinson’s diseases. In this work, two well characterized proteins, Colicin immunity proteins Im7 and Im9, where used as model for a structural study involving two different approaches to promote their denaturation/unfolding. Im7 and Im9 share a high sequence and structural homology, but despite that fact they fold with different kinetic mechanism in vitro. By using 1H-15N HSQC spectra as a main tool, we have undertaken a comparative study to identify the residues more affected during the denaturation process of Im7 and Im9 promoted by a physical effect, temperature increase, and by a chemical agent, urea. Our aim was to detect possible similarities that could give insight into the aspects that govern folding/unfolding transitions. The results from the temperature study show that the residues most perturbed with increasing temperature are mostly located in loop regions between helices, while urea targets preferably residues that are accessible and solvent exposed. Our study, points out that the ends of well-structured helices can concertedly unfold without entering the mid region residues in the same unfolding process. There seems to be a correlation between dynamic residues (most affected by temperature) and the residues in the regions most perturbed by urea. The results shown that entire loop regions on both proteins may act as concerted units during the unfolding process, and contribute for favorable interactions that delimit and stabilize native-like structural features on the urea-unfolded state, allowing buried regions to be less solvent exposed.
Fundação para a Ciência e a Tecnologia - PEst-C/EQB/LA0006/2011 and Project no. PTDC/QUI-QUI/098892/2008
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DuRose, Jenny Bratlien. "The unfolded protein response integrating stress signals from the endoplasmic reticulum to the nucleolus /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3330123.
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Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed November 13, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Cedras, Gillian. "The in vitro detection and measurement of the unfolded protein response in Saccharomyces cerevisiae." University of the Western Cape, 2018. http://hdl.handle.net/11394/6743.
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>Magister Scientiae - MScBioethanol is currently the most widely used biofuel and can be used as a direct replacement for current fossil fuel based transportation fuels. Consolidated bioprocessing (CBP), in which bioethanol is produced in a single reactor by a single microorganism, is a cost-effective way of producing bioethanol in a second generation process using lignocellulosic biomass as feedstock. The yeast Saccharomyces cerevisiae possesses industrially desirable traits for ethanol production and is able to produce heterologous cellulases, which are required for CBP. However, S. cerevisiae produces low titres of cellulases and one suspected reason for this is the stress caused by the heterologous proteins that induce the unfolded protein response (UPR). The UPR is a stress response pathway that will either lead to increased folding capacity within the ER or to degradation of these proteins and possibly apoptosis of the cell. It is thus beneficial to be able to determine when and to what extent the UPR is active during CBP organism development. Current methods of measuring the UPR include RNA and reverse transcriptase qPCR (r.t.qPCR) measurements, which can be cumbersome and expensive. The purpose of this study was to develop a vector based biosensor that will detect and quantify UPR activation. The vector consisted of either the T.r.xyn2 or eGFP reporter genes under the control of the S. cerevisiae HAC1p or KAR2p promoters. HAC1 and KAR2 are important regulators of UPR as their activation allows the UPR to achieve its function. The eGFP reporter under the transcriptional control of KAR2p was shown to be the superior combination due to the improved dynamic range when the UPR was induced in transformed S. cerevisiae strains by the stress inducer, tunicamycin. This UPR biosensor also proved to be more sensitive when measuring UPR induction in cellulase producing strains, depicting significant differences, compared to previous r.t.qPCR based tests which were unable to detect these differences. We thus developed a UPR biosensor that has greater sensitivity for changes in UPR induction compared to RNA based methods and the first KAR2p based UPR biosensor plasmid that allowed for more accurate detection and measurement of the UPR in cellulase secreting S. cerevisiae strains. The ability to quantify UPR induction will assist in identifying candidate cellulase genes that do not greatly induce the UPR, making them ideal to use in developing CBP yeasts.
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Seiferling, Dominic [Verfasser], Aleksandra [Akademischer Betreuer] Trifunovic, and Elena [Akademischer Betreuer] Rugarli. "Regulation of the mammalian mitochondrial unfolded protein response / Dominic Seiferling. Gutachter: Aleksandra Trifunovic ; Elena Rugarli." Köln : Universitäts- und Stadtbibliothek Köln, 2016. http://d-nb.info/1097506851/34.
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Stefani, Chrysoula Ioanna. "Unravelling the progression of unfolded protein Rresponse in a model system of familial Alzheimer's disease." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/42359.
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Alzheimer's disease (AD) is the most common form of dementia disorders and, yet, there is no preventative or curative treatment. It is associated with the progressive loss of memory and cognition and clinically divided into sporadic and familial forms. Familial Alzheimer's disease (FAD) has predominantly a genetic predisposition with inherited mutations in the amyloid-β precursor protein (APP) and presinilin genes, which promote APP processing through the amyloidogenic pathway. This results in the release of the Aβ peptide, a major neurotoxic agent in AD progression. Accumulation of unfolded and misfolded disease-specific proteins (including Aβ and tau proteins) in neuronal cells perturbs endoplasmic reticulum (ER) homeostasis, leading to the onset of a cellular stress cascade called unfolded protein response (UPR), markers of which are upregulated in AD brain specimens. This suggests a possible role for ER stress in activation and the pathogenesis of AD. The research aimed to investigate the dynamic response of the UPR in an experimental model system of the disease combined with a computational model. For this purpose human neuroblastoma cell lines overexpressing the wild-type (APPWT) and two mutant forms of APP (APPMUT) associated with FAD were generated. Gene expression analysis of UPR markers revealed that overexpression of APP induces preconditioning of ER stress in all cell lines but with a stronger response in FAD-associated mutants. The progression sequence of UPR in APPWT and APPMUT was investigated in a time-course manner following the application of chemical stress. The results revealed that APPMUT exhibited the highest global response to chemically induced stress with a similar pattern. A computational model of the mammalian UPR was then generated and used to understand the dynamics of UPR. The model was able to reproduce our experimental data, which included pre-existing genetic factors (mutations in APP-associated with FAD) and a mimic of environmental triggers (induction of stress) consequently triggering the stress response. It suggested a different protein load and magnitude of transcriptional activation upon stress among the three cell lines. This was followed by in silico case studies exploring the effect of drugs targeting different branches of the UPR. This study proposes a novel multidisciplinary platform that could be further used for the development of therapeutics for AD. As the familial and sporadic form of the disease have similar neuropathological characteristics, drugs efficacious for FAD will also be beneficial for the most common form of AD.
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Lai, Wai-lung. "The role of unfolded protein response in the cytotoxicity mechanism of N-(4-hydroxyphenyl)retinamide." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B39793928.
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Sudsaward, S. "Regulation of autophagy, endoplasmic reticulum and unfolded protein response by glucocorticoids in physiology and disease." Thesis, University of Salford, 2018. http://usir.salford.ac.uk/48217/.
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Acute lymphoblastic leukemia (ALL) is the most frequent cancer in children, and although highly treatable, challenges remain due to significant side effects of therapy and the poor outcome for some patients. Synthetic glucocorticoid, Dexamethasone (Dex), has been used to treat several haematological malignancies including ALL. To understand better how GC-resistant leukemic cells respond to Dex treatment, combination treatment of Dexamethasone with Chloroquine (CLQ), Thapsigargin (TG), Rotenone (ROT) and Bortezomib (BTZ) were used to investigate the role of autophagy, endoplasmic reticulum stress (ER stress) and unfolded protein response (UPR) respectively, in acute lymphoblastic leukemia cell lines including CEM-C1-15, CEM-C7-14 and Molt4. The results showed that autophagy inhibition by CLQ increased cell death and combination treatment with Dex exerted cytotoxic effect in all cells. These findings suggest that autophagy may play the important role to protect the ALL cells from GC-induced cell apoptosis, especially in GC-resistant cells. Furthermore, ER stress inducer, TG, treatment in the absence and presence of dexamethasone resulted in increase of ER chaperone proteins GRP78 and GRP94 in CEM-C7-14 cells. This is potentially related to increased cell death and may play a role in ER stress mediated cell apoptosis. Protein degradation inhibition by BTZ sensitised the ALL cells to the treatments and combination conditions had synergistic effect in all leukemic cells. Reactive oxygen species assay indicated that increased ROS levels correlate with the increase in CEM cells death in ROT only and combination treatment with Dex. Interestingly, ER chaperone proteins GRP78 and GRP94 increase in the protein but not mRNA expression levels in Dexamethasone treated glucocorticoid-sensitive cells. These results suggested that GR regulated chaperone protein levels by indirect mechanism. Taken together, these findings suggest that autophagy may be acting as pro survival process in glucocorticoid resistant leukemia. In GC sensitive leukemia, mitochondria and ER are important for GCs dependent cell death and GCs mediated increase in the GRPs protein levels that could lead to cell apoptosis. These results, if confirmed in clinical samples may have prognostic, diagnostic and therapeutic future use in medicine.
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Köhler, Fabian [Verfasser], and Barbara [Akademischer Betreuer] Conradt. "Analysis of the mitochondrial unfolded protein response in Caenorhabditis elegans / Fabian Köhler ; Betreuer: Barbara Conradt." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2020. http://d-nb.info/1227188307/34.
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El-Hadi, Mariam. "Mdg1 und die UPR - Stellung und Funktion des Hsp40-Chaperones in der Unfolded Protein Response." [S.l. : s.n.], 2005.
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Sanchez, Katheryn Marie. "Ultraviolet resonance Raman and fluorescence studies of folded and unfolded conformations of the membrane protein OmpA." Diss., [La Jolla] : University of California, San Diego, 2010. http://wwwlib.umi.com/cr/ucsd/fullcit?p3397317.
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Thesis (Ph. D.)--University of California, San Diego, 2010.Title from first page of PDF file (viewed April 7, 2010). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Omikorede, Omotola. "The role of ER stress and the unfolded protein response in obesity associated type 2 diabetes." Thesis, University of Leicester, 2012. http://hdl.handle.net/2381/10182.
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Pancreatic β-cell dysfunction plays a central role in the pathogenesis of type 2 diabetes. This dysfunction is characterised by secretory defects in the β-cells and the loss of β-cell mass, at least in part secondary to increased β-cell apoptosis. Although the mechanisms through which β-cell dysfunction develops are unclear, accumulating evidence suggests that elevated levels of circulating free fatty acids (FFAs) as can occur under conditions of obesity, play a role in the pathogenesis of type 2 diabetes. It has been suggested that endoplasmic reticulum (ER) stress and the resulting unfolded protein response (UPR) play a role in FFA induced β-cell dysfunction. This thesis was aimed at investigating the role of obesity induced ER stress in the development of β-cell dysfunction in type 2 diabetes. The UPR was induced in MIN6 β-cells in response to both the saturated fatty acid (FA) palmitate, and unsaturated fatty acid oleate. Palmitate however induced a more marked ER stress response in comparison to oleate. Although both FAs induced ER stress, only palmitate evoked apoptosis in the β-cells, indicative of the differential signalling by unsaturated and saturated fatty acids. ER stress and evidence of functional adaptation was also observed in islets obtained from Zucker and Zucker diabetic fatty (ZDF) rodent models of obesity. The development of β-cell dysfunction in the progression from obesity to obesity associated type 2 diabetes in the ZDF rats was however not accompanied by a further increase in ER stress markers. This suggests that ER stress signalling does not play a significant role in the development of β-cell dysfunction. In conclusion, the studies outlined in this thesis demonstrate that ER stress is induced in in vitro and in vivo models of β-cell lipotoxicity. It is however apparent, that ER stress does not contribute significantly to β-cell dysfunction and perhaps, only plays a small insignificant role in β-cell apoptosis in the pathogenesis of type 2 diabetes. It is hypothesised, that β-cell dysfunction develops in type 2 diabetes as a result of the inability of the β-cell to mount an additive UPR in response to ER stress.
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Sauer, Markus [Verfasser], and Lucie [Akademischer Betreuer] Carrier. "The unfolded protein response in Mybpc3-targeted mice with hypertrophic cardiomyopathy / Markus Sauer. Betreuer: Lucie Carrier." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2013. http://d-nb.info/1030366012/34.
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Eriksson, Mikael. "The complex internationalization process unfolded : The case of Atlas Copco’s entry into the Chinese mid-market." Doctoral thesis, Uppsala universitet, Företagsekonomiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-273700.
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Despite its contemporary relevance, we still have limited empirical knowledge about the forces underlying complex internationalization processes as when multinational corporations (MNCs) seek to enter new growing markets. Based on a real-time process study comprising ninety interviews and two hundred hours of observation made between 2009 and 2012, Atlas Copco’s entry into the Chinese mid-market was investigated. The intra-organizational analysis showed that three inter-related processes were underlying Atlas’ market entry and the results suggest that multiple interrelated motors may drive many contemporary internationalization processes. The processes identified are a sequential strategy process, an evolutionary process which shows that routines changed, and a political process. A somewhat surprising finding is that the main driver of internationalization according to received theory, the firm’s accumulated experiences, not only can drive internationalization, but may also hamper MNC managers’ possibilities to enter many of today’s new and growing markets. The findings add to our knowledge of the internationalization process in an increasingly complex international business setting, and especially highlight the need to distinguish between the sequential strategy process – more in line with received theory – and the other processes, in order to get a more full-fledged picture of what internationalization in large MNCs is all about.
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Berger, Emanuel Clemens [Verfasser]. "Impact of unfolded protein responses on intestinal epithelial homeostasis in genetically modified mouse models / Emanuel Berger." München : Verlag Dr. Hut, 2014. http://nbn-resolving.de/urn:nbn:de:101:1-2014081529049.
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Davies, Matthew. "Investigation of the unfolded protein response and other stress-related responses in distinct models of neurodegeneration." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/390653/.
Full textAbstract:
There is no cure for chronic neurodegenerative diseases and disease-modifying therapies are limited. In order to develop successful disease-modifying therapies the molecules and pathways that underpin early stages of disease, such as synapse loss, need to be better defined. Three distinct in vivo mouse models of neurodegeneration have been used to investigate molecular stress response molecules and pathways. These models are the ME7 prion model, the cysteine string protein alpha (CSP?) -/- model and a kainic acid model of excitotoxicity. In all cases hippocampal tissue from mice was used to investigate the neuropathology and associated stress-related pathways. The unfolded protein response (UPR) and other stress-related response molecules: immediate early genes (ATF3, c-Jun and c-Fos), activity-induced immediate early genes (Arc and Homer1a) and a cellular physiological and environmental damage stress sensor (GADD45?) were investigated. Biochemical and immunohistochemistry analysis revealed no evidence for a robust and classic UPR in any of the three models despite neuropathological changes associated with these distinct insults being evident. However, other stress-related response molecules were induced in these models and the induction of some of these occurred at the same time/prior to synapse loss suggesting that these are early responses and potential therapeutic targets for modifying neurodegenerative disease. Tissue analysis is confounded by cellular heterogeneity. To investigate discrete cell specific events laser capture microdissection (LCM) was used to isolate the cell bodies of dysfunctional CA3 pyramidal neurons across key stages of ME7 prion disease. Optimisation of LCM enabled enrichment of CA3 pyramidal neurons and targeted analysis of UPR molecules. mRNA analysis failed to show strong evidence for a robust induction of the UPR in these vulnerable CA3 pyramidal neurons. Total RNA has also been used for RNA sequencing to analyse differentially expressed genes and molecular pathways activated during prion disease progression. The aim of this targeted approach will be to resolve molecular targets and pathways which might mitigate the progression of chronic neurodegenerative diseases.
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Mousavizadeh, Leila [Verfasser], and Wolfram [Akademischer Betreuer] Brune. "Modulation of the Unfolded Protein Response by Kaposi's Sarcoma-associated herpesvirus / Leila Mousavizadeh ; Betreuer: Wolfram Brune." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2020. http://d-nb.info/1209676249/34.
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Berger, Emanuel [Verfasser]. "Impact of unfolded protein responses on intestinal epithelial homeostasis in genetically modified mouse models / Emanuel Berger." München : Verlag Dr. Hut, 2014. http://d-nb.info/1055863680/34.
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Clarke, Emily Jayne. "The unfolded protein response : a potential link between heterozygous mutations in GBA1 and Lewy body dementia?" Thesis, King's College London (University of London), 2018. https://kclpure.kcl.ac.uk/portal/en/theses/the-unfolded-protein-response(28b300fd-57f0-4e89-9fbb-6d65e0d30ee7).html.
Full textAbstract:
Lewy body dementia (LBD) is characterised by the deposition of a-synuclein containing Lewy bodies throughout cortical brain regions. Pathology is confounded by the co-occurrence of pathological Ab and tau deposition. LBD comprises dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD), distinguished by the timing of onset of classical symptoms: cognitive impairment occurs at least one year prior to motor impairment in DLB and vice versa in PDD. Currently, there are no disease modifying therapeutic agents for LBD. Heterozygous mutations in GBA1 have become established as the most common genetic risk factor for Parkinson’s disease and dementia with Lewy bodies. GBA1 encodes the lysosomal enzyme glucocerebrosidase. Deficient glucocerebrosidase activity causes accumulation of a-synuclein. Homozygous GBA1 mutation causes the lysosomal storage disorder Gaucher’s disease. In this thesis, a possible mechanism underlying the link between GBA1 mutation and LBD is investigated - the unfolded protein response (UPR). We hypothesise that the UPR is activated in response to mutant GBA1 but is unable to serve a protective function under increasing levels of stress. We also characterise the impact of heterozygous GBA1 mutation (D427V) on mice to establish whether a cognitive impairment phenotype is displayed which may be translational for the study of LBD. The results presented in this thesis support the activation of both IRE1a and PERK mediated UPR responses since we show increased expression of spliced XBP1 and CHOP in a L444P mutant GBA1 SH-SY5Y cell model. We also demonstrate spliced XBP1 ceases to be expressed under increasing cellular stress whilst CHOP expression continues. Since CHOP is associated with detrimental cell outcomes, predominantly initiation of apoptosis, we suggest that the imbalance of UPR responses towards CHOP mediated effects may potentially underlie pathological consequences associated with GBA1 mutation. Results presented in this thesis also reveal a previously unreported progressive cognitive decline in D427V/WT GBA1 mice. In conclusion, preventing the withdrawal of protective spliced XBP1 mediated effects and continued expression CHOP may be a therapeutic avenue for further investigation in D427V/WT GBA1 mice which show promising signs of being a translational model for LBD.