scholarly journals APY-1, a Novel Caenorhabditis elegans Apyrase Involved in Unfolded Protein Response Signalling and Stress Responses

2008 ◽  
Vol 19 (4) ◽  
pp. 1337-1345 ◽  
Author(s):  
D. Uccelletti ◽  
A. Pascoli ◽  
F. Farina ◽  
A. Alberti ◽  
P. Mancini ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Stress Responses ◽  
Sugar Metabolism ◽  
Protein Glycosylation ◽  
Premature Aging ◽  
C Elegans ◽  
Unfolded Protein ◽  
Protein Response

Protein glycosylation modulates a wide variety of intracellular events and dysfunction of the glycosylation pathway has been reported in a variety of human pathologies. Endo-apyrases have been suggested to have critical roles in protein glycosylation and sugar metabolism. However, deciphering the physiological relevance of Endo-apyrases activity has actually proved difficult, owing to their complexity and the functional redundancy within the family. We report here that a UDP/GDPase, homologous to the human apyrase Scan-1, is present in the membranes of Caenorhabditis elegans, encoded by the ORF F08C6.6 and hereinafter-named APY-1. We showed that ER stress induced by tunicamycin or high temperature resulted in increased transcription of apy-1. This increase was not observed in C. elegans mutants defective in ire-1 or atf-6, demonstrating the requirement of both ER stress sensors for up-regulation of apy-1. Depletion of APY-1 resulted in constitutively activated unfolded protein response. Defects in the pharynx and impaired organization of thin fibers in muscle cells were observed in adult worms depleted of APY-1. Some of the apy-1(RNAi) phenotypes are suggestive of premature aging, because these animals also showed accumulation of lipofuscin and reduced lifespan that was not dependent on the functioning of DAF-2, the receptor of the insulin/IGF-1 signaling pathway.

scholarly journals Balancing life with glycoconjugates: Monitoring unfolded protein response-mediated anti-angiogenic action of tunicamycin by Raman spectroscopy

2012 ◽  
Vol 84 (9) ◽  
pp. 1907-1918 ◽  
Author(s):  
Maria O. Longas ◽  
Ashok Kotapati ◽  
Kilari PVRK Prasad ◽  
Aditi Banerjee ◽  
Jesus Santiago ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Competitive Inhibitor ◽  
Protein Glycosylation ◽  
Endothelial Cell Proliferation ◽  
Dependent Manner ◽  
Unfolded Protein ◽  
And Function ◽  
Protein Response

Asparagine-linked protein glycosylation is a hallmark for glycoprotein structure and function. Its impairment by tunicamycin [a competitive inhibitor of N-acetylglucos-aminyl 1-phosphate transferase (GPT)] has been known to inhibit neo-vascularization (i.e., angiogenesis) in humanized breast tumor due to an induction of endoplasmic reticulum (ER) stress-mediated unfolded protein response (UPR). The studies presented here demonstrate that (i) tunicamycin inhibits capillary endothelial cell proliferation in a dose-dependent manner; (ii) treated cells are incapable of forming colonies upon its withdrawal; and (iii) tunicamycin treatment causes nuclear fragmentation. Tunicamycin-induced ER stress-mediated UPR event in these cells was studied with the aid of Raman spectroscopy, in particular, the interpretation of bands at 1672, 1684, and 1694 cm–1, which are characteristics of proteins and originate from C=O stretching vibrations of mono-substituted amides. In tunicamycin-treated cells, these bands decreased in area as follows: at 1672 cm–1 by 41.85 % at 3 h and 55.39 % at 12 h; at 1684 cm–1 by 20.63 % at 3 h and 40.08 % at 12 h; and also at 1994 cm–1 by 33.33 % at 3 h and 32.92 % at 12 h, respectively. Thus, in the presence of tunicamycin, newly synthesized protein chains fail to arrange properly into their final secondary and/or tertiary structures, and the random coils they form had undergone further degradation.

scholarly journals Four glial cells regulate ER stress resistance and longevity via neuropeptide signaling in C. elegans

Science ◽  
2020 ◽  
Vol 367 (6476) ◽  
pp. 436-440 ◽  
Author(s):  
Ashley E. Frakes ◽  
Melissa G. Metcalf ◽  
Sarah U. Tronnes ◽  
Raz Bar-Ziv ◽  
Jenni Durieux ◽  
...  
Keyword(s):  
Er Stress ◽  
Life Span ◽  
Glial Cells ◽  
Stress Responses ◽  
Stress Resistance ◽  
Life Span Extension ◽  
C Elegans ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

The ability of the nervous system to sense cellular stress and coordinate protein homeostasis is essential for organismal health. Unfortunately, stress responses that mitigate disturbances in proteostasis, such as the unfolded protein response of the endoplasmic reticulum (UPRER), become defunct with age. In this work, we expressed the constitutively active UPRER transcription factor, XBP-1s, in a subset of astrocyte-like glia, which extended the life span in Caenorhabditis elegans. Glial XBP-1s initiated a robust cell nonautonomous activation of the UPRER in distal cells and rendered animals more resistant to protein aggregation and chronic ER stress. Mutants deficient in neuropeptide processing and secretion suppressed glial cell nonautonomous induction of the UPRER and life-span extension. Thus, astrocyte-like glial cells play a role in regulating organismal ER stress resistance and longevity.

scholarly journals A survival pathway for Caenorhabditis elegans with a blocked unfolded protein response

2002 ◽  
Vol 158 (4) ◽  
pp. 639-646 ◽  
Author(s):  
Fumihiko Urano ◽  
Marcella Calfon ◽  
Takunari Yoneda ◽  
Chi Yun ◽  
Moni Kiraly ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Target Genes ◽  
Extracellular Proteins ◽  
Type I ◽  
Unfolded Protein ◽  
A Genome ◽  
Client Proteins ◽  
Protein Response

The unfolded protein response (UPR) counteracts stress caused by unprocessed ER client proteins. A genome-wide survey showed impaired induction of many UPR target genes in xbp-1 mutant Caenorhabditis elegans that are unable to signal in the highly conserved IRE1-dependent UPR pathway. However a family of genes, abu (activated in blocked UPR), was induced to higher levels in ER-stressed xbp-1 mutant animals than in ER-stressed wild-type animals. RNA-mediated interference (RNAi) inactivation of a representative abu family member, abu-1 (AC3.3), activated the ER stress marker hsp-4::gfp in otherwise normal animals and killed 50% of ER-stressed ire-1 and xbp-1 mutant animals. Abu-1(RNAi) also enhanced the effect of inactivation of sel-1, an ER-associated protein degradation gene. The nine abu genes encode highly related type I transmembrane proteins whose lumenal domains have sequence similarity to a mammalian cell surface scavenger receptor of endothelial cells that binds chemically modified extracellular proteins and directs their lysosomal degradation. Our findings that ABU-1 is an intracellular protein located within the endomembrane system that is induced by ER stress in xbp-1 mutant animals suggest that ABU proteins may interact with abnormal ER client proteins and this function may be particularly important in animals with an impaired UPR.

scholarly journals Autophagy, endoplasmic reticulum stress and the unfolded protein response in intracerebral hemorrhage

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Mingming Niu ◽  
Xiaohong Dai ◽  
Wei Zou ◽  
Xueping Yu ◽  
Wei Teng ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Intracerebral Hemorrhage ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Stress Responses ◽  
Secondary Brain Injury ◽  
Cell Homeostasis ◽  
Unfolded Protein ◽  
The Unfolded Protein Response ◽  
Protein Response

AbstractIntracerebral hemorrhage (ICH) is a subtype of stroke that is followed by primary and secondary brain injury. As a result of the injury, cell metabolism is disrupted and a series of stress responses are activated, such as endoplasmic reticulum (ER) stress and the unfolded protein response (UPR), leading to the re-establishment of cell homeostasis or cell death. As an important mechanism of cell homeostasis, autophagy has been widely studied, and the associations between autophagy, ER stress, and the UPR have also been demonstrated. Whether these mechanisms are beneficial or detrimental remains a matter of controversy, but there is no doubt as to their vital functions. An understanding of the mechanisms of injury and recovery after ICH is crucial to develop therapeutic strategies. In this review, we summarize the related studies and highlight the roles of autophagy, ER stress, and the UPR in disease, especially in ICH. We also provide an overview of therapeutic approaches that target autophagy, and we discuss the prospects for modulating autophagy, ER stress, and UPR mechanisms in ICH therapy.

scholarly journals Two human metabolites rescue a C. elegans model of Alzheimer’s disease via a cytosolic unfolded protein response

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Priyanka Joshi ◽  
Michele Perni ◽  
Ryan Limbocker ◽  
Benedetta Mannini ◽  
Sam Casford ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Unfolded Protein Response ◽  
Neurodegenerative Disorders ◽  
C Elegans ◽  
Unfolded Protein ◽  
Model Of Alzheimer’S Disease ◽  
Age Related ◽  
Parkinson’S Diseases ◽  
Protein Response

AbstractAge-related changes in cellular metabolism can affect brain homeostasis, creating conditions that are permissive to the onset and progression of neurodegenerative disorders such as Alzheimer’s and Parkinson’s diseases. Although the roles of metabolites have been extensively studied with regard to cellular signaling pathways, their effects on protein aggregation remain relatively unexplored. By computationally analysing the Human Metabolome Database, we identified two endogenous metabolites, carnosine and kynurenic acid, that inhibit the aggregation of the amyloid beta peptide (Aβ) and rescue a C. elegans model of Alzheimer’s disease. We found that these metabolites act by triggering a cytosolic unfolded protein response through the transcription factor HSF-1 and downstream chaperones HSP40/J-proteins DNJ-12 and DNJ-19. These results help rationalise previous observations regarding the possible anti-ageing benefits of these metabolites by providing a mechanism for their action. Taken together, our findings provide a link between metabolite homeostasis and protein homeostasis, which could inspire preventative interventions against neurodegenerative disorders.

scholarly journals Effectors Targeting the Unfolded Protein Response during Intracellular Bacterial Infection

2021 ◽  
Vol 9 (4) ◽  
pp. 705
Author(s):  
Manal H. Alshareef ◽  
Elizabeth L. Hartland ◽  
Kathleen McCaffrey
Keyword(s):  
Bacterial Infection ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Host Defense ◽  
Effector Proteins ◽  
Dual Nature ◽  
Unfolded Protein ◽  
Bacterial Replication ◽  
The Unfolded Protein Response ◽  
Protein Response

The unfolded protein response (UPR) is a homeostatic response to endoplasmic reticulum (ER) stress within eukaryotic cells. The UPR initiates transcriptional and post-transcriptional programs to resolve ER stress; or, if ER stress is severe or prolonged, initiates apoptosis. ER stress is a common feature of bacterial infection although the role of the UPR in host defense is only beginning to be understood. While the UPR is important for host defense against pore-forming toxins produced by some bacteria, other bacterial effector proteins hijack the UPR through the activity of translocated effector proteins that facilitate intracellular survival and proliferation. UPR-mediated apoptosis can limit bacterial replication but also often contributes to tissue damage and disease. Here, we discuss the dual nature of the UPR during infection and the implications of UPR activation or inhibition for inflammation and immunity as illustrated by different bacterial pathogens.

scholarly journals Unfolded protein response triggers differential apoptotic mechanisms in ovaries and early embryos exposed to maternal type 1 diabetes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aslı Okan ◽  
Necdet Demir ◽  
Berna Sozen
Keyword(s):  
Embryonic Development ◽  
Er Stress ◽  
Unfolded Protein Response ◽  
Molecular Mechanisms ◽  
Early Embryonic Development ◽  
Unfolded Protein ◽  
Caspase 12 ◽  
Early Embryos ◽  
Protein Response

AbstractDiabetes mellitus (DM) has profound effects on the female mammalian reproductive system, and early embryonic development, reducing female reproductive outcomes and inducing developmental programming in utero. However, the underlying cellular and molecular mechanisms remain poorly defined. Accumulating evidence implicates endoplasmic reticulum (ER)-stress with maternal DM associated pathophysiology. Yet the direct pathologies and causal events leading to ovarian dysfunction and altered early embryonic development have not been determined. Here, using an in vivo mouse model of Type 1 DM and in vitro hyperglycaemia-exposure, we demonstrate the activation of ER-stress within adult ovarian tissue and pre-implantation embryos. In diabetic ovaries, we show that the unfolded protein response (UPR) triggers an apoptotic cascade by the co-activation of Caspase 12 and Cleaved Caspase 3 transducers. Whereas DM-exposed early embryos display differential ER-associated responses; by activating Chop in within embryonic precursors and Caspase 12 within placental precursors. Our results offer new insights for understanding the pathological effects of DM on mammalian ovarian function and early embryo development, providing new evidence of its mechanistic link with ER-stress in mice.

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