| 1. |
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| 2. |
- Ahmadpour, Doryaneh, 1973, et al.
(författare)
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Hitchhiking on vesicles: a way to harness age-related proteopathies?
- 2020
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Ingår i: FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 287:23, s. 5068-5079
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Tidskriftsartikel (refereegranskat)abstract
- Central to proteopathies and leading to most age-related neurodegenerative disorders is a failure in protein quality control (PQC). To harness the toxicity of misfolded and damaged disease proteins, such proteins are either refolded, degraded by temporal PQC, or sequestered by spatial PQC into specific, organelle-associated, compartments within the cell. Here, we discuss the impact of vesicle trafficking pathways in general, and syntaxin 5 in particular, as key players in spatial PQC directing misfolded proteins to the surface of vacuole and mitochondria, which facilitates their clearance and detoxification. Since boosting vesicle trafficking genetically can positively impact on spatial PQC and make cells less sensitive to misfolded disease proteins, we speculate that regulators of such trafficking might serve as therapeutic targets for age-related neurological disorders.
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| 3. |
- Aliashkevich, Alena, et al.
(författare)
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LD-transpeptidases : the great unknown among the peptidoglycan cross-linkers
- 2022
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 289:16, s. 4718-4730
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Forskningsöversikt (refereegranskat)abstract
- The peptidoglycan (PG) cell wall is an essential polymer for the shape and viability of bacteria. Its protective role is in great part provided by its mesh-like character. Therefore, PG-cross-linking enzymes like the penicillin-binding proteins (PBPs) are among the best targets for antibiotics. However, while PBPs have been in the spotlight for more than 50 years, another class of PG-cross-linking enzymes called LD-transpeptidases (LDTs) seemed to contribute less to PG synthesis and, thus, has kept an aura of mystery. In the last years, a number of studies have associated LDTs with cell wall adaptation to stress including β-lactam antibiotics, outer membrane stability, and toxin delivery, which has shed light onto the biological meaning of these proteins. Furthermore, as some species display a great abundance of LD-cross-links in their cell wall, it has been hypothesized that LDTs could also be the main synthetic PG-transpeptidases in some bacteria. In this review, we introduce these enzymes and their role in PG biosynthesis and we highlight the most recent advances in understanding their biological role in diverse species.
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| 4. |
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| 5. |
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| 6. |
- Andersson, Annika, et al.
(författare)
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Membrane integration and topology of RIFIN and STEVOR proteins of the Plasmodium falciparum parasite
- 2020
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 287:13, s. 2744-2762
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Tidskriftsartikel (refereegranskat)abstract
- The malarial parasite Plasmodium exports its own proteins to the cell surfaces of red blood cells (RBCs) during infection. Examples of exported proteins include members of the repetitive interspersed family (RIFIN) and subtelomeric variable open reading frame (STEVOR) family of proteins from Plasmodium falciparum. The presence of these parasite-derived proteins on surfaces of infected RBCs triggers the adhesion of infected cells to uninfected cells (rosetting) and to the vascular endothelium potentially obstructing blood flow. While there is a fair amount of information on the localization of these proteins on the cell surfaces of RBCs, less is known about how they can be exported to the membrane and the topologies they can adopt during the process. The first step of export is plausibly the cotranslational insertion of proteins into the endoplasmic reticulum (ER) of the parasite, and here, we investigate the insertion of three RIFIN and two STEVOR proteins into the ER membrane. We employ a well-established experimental system that uses N-linked glycosylation of sites within the protein as a measure to assess the extent of membrane insertion and the topology it assumes when inserted into the ER membrane. Our results indicate that for all the proteins tested, transmembranes (TMs) 1 and 3 integrate into the membrane, so that the protein assumes an overall topology of Ncyt-Ccyt. We also show that the segment predicted to be TM2 for each of the proteins likely does not reside in the membrane, but is translocated to the lumen.
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| 7. |
- Bajusz, Csaba, et al.
(författare)
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The nuclear activity of the actin-binding Moesin protein is necessary for gene expression in Drosophila
- 2021
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 288:16, s. 4812-4832
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Tidskriftsartikel (refereegranskat)abstract
- Ezrin-Radixin-Moesin (ERM) proteins play an essential role in the cytoplasm by cross-linking actin filaments with plasma membrane proteins. Research has identified the nuclear localization of ERMs, as well as the involvement of a single Drosophila ERM protein, Moesin, in nuclear mRNA exports. However, the question of how important the nuclear activity of ERM proteins are for the life of an organism has so far not been explored. Here, we present the first attempt to reveal the in vivo relevance of nuclear localization of Moesin in Drosophila. With the help of a nuclear export signal, we decreased the amount of Moesin in the nuclei of the animals. Furthermore, we observed various developmental defects, demonstrating the importance of ERM function in the nucleus for the first time. Transcriptome analysis of the mutant flies revealed that the lack of nuclear Moesin function leads to expression changes in nearly 700 genes, among them heat-shock genes. This result together with additional findings revealed that in Drosophila the expression of protein chaperones requires the nuclear functions of Moesin.
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| 8. |
- Bhalerao, Rishikesh P.
(författare)
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When to branch: seasonal control of shoot architecture in trees
- 2021
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Ingår i: The Febs Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 289, s. 8062-8070
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Tidskriftsartikel (refereegranskat)abstract
- Long-lived perennial plants optimize their shoot architecture by responding to seasonal cues. The main strategy used by plants of temperate and boreal regions with respect to surviving the extremely unfavourable conditions of winter comprises the protection of their apical and lateral meristematic tissues. This involves myriads of transcriptional, translational and metabolic changes in the plants because shoot architecture is controlled by multiple pathways that regulate processes such as bud formation and flowering, small RNAs, environmental factors (especially light quality, photoperiod and temperature), hormones, and sugars. Recent studies have begun to reveal how these pathways are recruited for the seasonal adaptation and regulation of shoot architecture in perennial plants, including the role of a regulatory module consisting of antagonistic players terminal flower 1 (TFL1) and like-ap1 (LAP1) in the hybrid aspen. Here, we review recent progress in our understanding of the genetic control of shoot architecture in perennials compared to in annuals.
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| 9. |
- Cavinato, Maria, et al.
(författare)
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Targeting cellular senescence based on interorganelle communication, multilevel proteostasis, and metabolic control
- 2021
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 228:12, s. 3834-3854
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Forskningsöversikt (refereegranskat)abstract
- Cellular senescence, a stable cell division arrest caused by severe damage and stress, is a hallmark of aging in vertebrates including humans. With progressing age, senescent cells accumulate in a variety of mammalian tissues, where they contribute to tissue aging, identifying cellular senescence as a major target to delay or prevent aging. There is an increasing demand for the discovery of new classes of small molecules that would either avoid or postpone cellular senescence by selectively eliminating senescent cells from the body (i.e., 'senolytics') or inactivating/switching damage-inducing properties of senescent cells (i.e., 'senostatics/senomorphics'), such as the senescence-associated secretory phenotype. Whereas compounds with senolytic or senostatic activity have already been described, their efficacy and specificity has not been fully established for clinical use yet. Here, we review mechanisms of senescence that are related to mitochondria and their interorganelle communication, and the involvement of proteostasis networks and metabolic control in the senescent phenotype. These cellular functions are associated with cellular senescence in in vitro and in vivo models but have not been fully exploited for the search of new compounds to counteract senescence yet. Therefore, we explore possibilities to target these mechanisms as new opportunities to selectively eliminate and/or disable senescent cells with the aim of tissue rejuvenation. We assume that this research will provide new compounds from the chemical space which act as mimetics of caloric restriction, modulators of calcium signaling and mitochondrial physiology, or as proteostasis optimizers, bearing the potential to counteract cellular senescence, thereby allowing healthy aging.
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| 10. |
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| 11. |
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| 12. |
- Doultsinos, D., et al.
(författare)
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Peptidomimetic-based identification of FDA-approved compounds inhibiting IRE1 activity
- 2021
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Ingår i: Febs Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 288:3, s. 945-960
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Tidskriftsartikel (refereegranskat)abstract
- Inositol-requiring enzyme 1 (IRE1) is a bifunctional serine/threonine kinase and endoribonuclease that is a major mediator of the unfolded protein response (UPR) during endoplasmic reticulum (ER) stress. Tumour cells experience ER stress due to adverse environmental cues such as hypoxia or nutrient shortage and high metabolic/protein-folding demand. To cope with those stresses, cancer cells utilise IRE1 signalling as an adaptive mechanism. Here, we report the discovery of the FDA-approved compounds methotrexate, cefoperazone, folinic acid and fludarabine phosphate as IRE1 inhibitors. These were identified through a structural exploration of the IRE1 kinase domain using IRE1 peptide fragment docking and further optimisation and pharmacophore development. The inhibitors were verified to have an impact on IRE1 activityin vitroand were tested for their ability to sensitise human cell models of glioblastoma multiforme (GBM) to chemotherapy. We show that all molecules identified sensitise glioblastoma cells to the standard-of-care chemotherapy temozolomide (TMZ).
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| 13. |
- Georgoulia, Panagiota S., et al.
(författare)
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Deciphering the molecular mechanism of FLT3 resistance mutations
- 2020
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 287:15, s. 3200-3220
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Tidskriftsartikel (refereegranskat)abstract
- FMS-like tyrosine kinase 3 (FLT3) has been found to be mutated in 30% of acute myeloid leukaemia patients. Small-molecule inhibitors targeting FLT3 that are currently approved or still undergoing clinical trials are subject to drug resistance due to FLT3 mutations. How these mutations lead to drug resistance is hitherto poorly understood. Herein, we studied the molecular mechanism of the drug resistance mutations D835N, Y842S and M664I, which confer resistance against the most advanced inhibitors, quizartinib and PLX3397 (pexidartinib), using enzyme kinetics and computer simulations. In vitro kinase assays were performed to measure the comparative catalytic activity of the native protein and the mutants, using a bacterial expression system developed to this aim. Our results reveal that the differential drug sensitivity profiles can be rationalised by the dynamics of the protein-drug interactions and perturbation of the intraprotein contacts upon mutations. Drug binding induced a single conformation in the native protein, whereas multiple conformations were observed otherwise (in the mutants or in the absence of drugs). The end-point kinetics measurements indicated that the three resistant mutants conferred catalytic activity that is at least as high as that of the reference without such mutations. Overall, our calculations and measurements suggest that the structural dynamics of the drug-resistant mutants that affect the active state and the increased conformational freedom of the remaining inactive drug-bound population are the two major factors that contribute to drug resistance in FLT3 harbouring cancer cells. Our results explain the mechanism of drug resistance mutations and can aid to the design of more effective tyrosine kinase inhibitors.
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| 14. |
- Haataja, Topi, et al.
(författare)
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Enzyme kinetics by GH7 cellobiohydrolases on chromogenic substrates is dictated by non-productive binding : insights from crystal structures and MD simulation
- 2023
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 290:2, s. 379-399
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Tidskriftsartikel (refereegranskat)abstract
- Cellobiohydrolases (CBHs) in the glycoside hydrolase family 7 (GH7) (EC3.2.1.176) are the major cellulose degrading enzymes both in industrial settings and in the context of carbon cycling in nature. Small carbohydrate conjugates such as p-nitrophenyl-beta-d-cellobioside (pNPC), p-nitrophenyl-beta-d-lactoside (pNPL) and methylumbelliferyl-beta-d-cellobioside have commonly been used in colorimetric and fluorometric assays for analysing activity of these enzymes. Despite the similar nature of these compounds the kinetics of their enzymatic hydrolysis vary greatly between the different compounds as well as among different enzymes within the GH7 family. Through enzyme kinetics, crystallographic structure determination, molecular dynamics simulations, and fluorometric binding studies using the closely related compound o-nitrophenyl-beta-d-cellobioside (oNPC), in this work we examine the different hydrolysis characteristics of these compounds on two model enzymes of this class, TrCel7A from Trichoderma reesei and PcCel7D from Phanerochaete chrysosporium. Protein crystal structures of the E212Q mutant of TrCel7A with pNPC and pNPL, and the wildtype TrCel7A with oNPC, reveal that non-productive binding at the product site is the dominating binding mode for these compounds. Enzyme kinetics results suggest the strength of non-productive binding is a key determinant for the activity characteristics on these substrates, with PcCel7D consistently showing higher turnover rates (k(cat)) than TrCel7A, but higher Michaelis-Menten (K-M) constants as well. Furthermore, oNPC turned out to be useful as an active-site probe for fluorometric determination of the dissociation constant for cellobiose on TrCel7A but could not be utilized for the same purpose on PcCel7D, likely due to strong binding to an unknown site outside the active site.
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| 15. |
- Haataja, Topi, et al.
(författare)
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The crystal structure of RsSymEG1 reveals a unique form of smaller GH7 endoglucanases alongside GH7 cellobiohydrolases in protist symbionts of termites
- 2024
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Ingår i: The Febs Journal. - 1742-464X .- 1742-4658. ; 291, s. 1168-1185
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Tidskriftsartikel (refereegranskat)abstract
- Glycoside hydrolase family 7 (GH7) cellulases are key enzymes responsible for carbon cycling on earth through their role in cellulose degradation and constitute highly important industrial enzymes as well. Although these enzymes are found in a wide variety of evolutionarily distant organisms across eukaryotes, they exhibit remarkably conserved features within two groups: exo-acting cellobiohydrolases and endoglucanases. However, recently reports have emerged of a separate clade of GH7 endoglucanases from protist symbionts of termites that are 60-80 amino acids shorter. In this work, we describe the first crystal structure of a short GH7 endoglucanase, RsSymEG1, from a symbiont of the lower termite Reticulitermes speratus. A more open flat surface and shorter loops around the non-reducing end of the cellulose-binding cleft indicate enhanced access to cellulose chains on the surface of cellulose microfibrils. Additionally, when comparing activities on polysaccharides to a typical fungal GH7 endoglucanase (Trichoderma longibrachiatum Cel7B), RsSymEG1 showed significantly faster initial hydrolytic activity. We also examine the prevalence and diversity of GH7 enzymes that the symbionts provide to the termite host, compare overall structures and substrate binding between cellobiohydrolase and long and short endoglucanase, and highlight the presence of similar short GH7s in other organisms.
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| 16. |
- Hu, Min, et al.
(författare)
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Regulatory mechanisms of HMGB1 and its receptors in polycystic ovary syndrome-driven gravid uterine inflammation. : Gravid uterine HMGB1 and TLR2/4 in PCOS
- 2023
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Ingår i: The FEBS journal. - : Wiley. - 1742-4658 .- 1742-464X. ; 290:7, s. 1874-1906
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Tidskriftsartikel (refereegranskat)abstract
- High-mobility group box 1 (HMGB1) is critical for inflammatory homeostasis and successful pregnancy, and there is a strong association between elevated levels of HMGB1, polycystic ovary syndrome (PCOS), chronic inflammation, and pregnancy loss. However, the mechanisms responsible for PCOS-driven regulation of uterine HMGB1 and its candidate receptors (toll-like receptor (TLR) 2 and 4) and inflammatory responses during pregnancy remain unclear. In this study, we found a gestational stage-dependent decrease in uterine HMGB1 and TLR4 protein abundance in rats during normal pregnancy. We demonstrated that increased expression of HMGB1, TLR2, and TLR4 proteins was associated with activation of inflammation-related signaling pathways in the gravid uterus exposed to 5α-dihydrotestosterone and insulin, mimicking the clinical features (hyperandrogenism and insulin resistance) of PCOS, and this elevation was completely inhibited by treatment with the androgen receptor (AR) antagonist flutamide. Interestingly, acute exposure to lipopolysaccharide suppressed HMGB1, TLR4, and inflammation-related protein abundance but did not affect androgen levels or AR expression in the gravid uterus with viable fetuses. Furthermore, immunohistochemical analysis revealed that, in addition to being localized predominately in the nuclear compartment, HMGB1 immunoreactivity was also detected in the cytoplasm in the PCOS-like rat uterus, PCOS endometrium, and pregnant rat uterus with hemorrhagic and resorbed fetuses, possibly via activation of nuclear factor κB signaling. These results suggest that both AR-dependent and AR-independent mechanisms contribute to the modulation of HMGB1/TLR2/TLR4-mediated uterine inflammation. We propose that elevation of HMGB1 and its receptors and disruption of the pro-/anti-inflammatory balance in the gravid uterus may participate in the pathophysiology of PCOS-associated pregnancy loss.
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| 17. |
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| 18. |
- Islam, Tohidul, et al.
(författare)
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Apolipoprotein E impairs amyloid-β fibril elongation and maturation
- 2020
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Ingår i: The FEBS Journal. - : Wiley-Blackwell. - 1742-464X .- 1742-4658. ; 287:6, s. 1208-1219
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is strongly linked to amyloid depositions of the Aβ peptide (Aβ). The lipid-binding protein apolipoprotein E (ApoE) has been found to interfere with Aβ amyloid formation and to exert a strong clinical impact to the pathology of AD. The APOE gene exists in three allelic isoforms represented by APOE ε2, APOE ε3, and APOE ε4. Carriers of the APOE ε4 variant display a gene dose-dependent increased risk of developing the disease. Aβ amyloids are formed via a nucleation-dependent mechanism where free monomers are added onto a nucleus in a template-dependent manner. Using a combination of surface plasmon resonance and thioflavin-T assays, we here show that ApoE can target the process of fibril elongation and that its interference effectively prevents amyloid maturation. We expose a complex equilibrium where the concentration of ApoE, Aβ monomers, and the amount of already formed Aβ fibrils will affect the relative proportion and formation rate of mature amyloids versus alternative assemblies. The result illustrates a mechanism which may affect both the clearance rate of Aβ assemblies in vivo and the population of cytotoxic Aβ assemblies.
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| 19. |
- Jakubec, Martin, et al.
(författare)
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Cholesterol-containing lipid nanodiscs promote an α-synuclein binding mode that accelerates oligomerization
- 2021
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 288:6, s. 1887-1905
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Tidskriftsartikel (refereegranskat)abstract
- Dysregulation of the biosynthesis of cholesterol and other lipids has been implicated in many neurological diseases, including Parkinson's disease. Misfolding of α‐synuclein (α‐Syn), the main actor in Parkinson's disease, is associated with changes in a lipid environment. However, the exact molecular mechanisms underlying cholesterol effect on α‐Syn binding to lipids as well as α‐Syn oligomerization and fibrillation remain elusive, as does the relative importance of cholesterol compared to other factors. We probed the interactions and fibrillation behaviour of α‐Syn using styrene–maleic acid nanodiscs, containing zwitterionic and anionic lipid model systems with and without cholesterol. Surface plasmon resonance and thioflavin T fluorescence assays were employed to monitor α‐Syn binding, as well as fibrillation in the absence and presence of membrane models. 1H‐15N‐correlated NMR was used to monitor the fold of α‐Syn in response to nanodisc binding, determining individual residue apparent affinities for the nanodisc‐contained bilayers. The addition of cholesterol inhibited α‐Syn interaction with lipid bilayers and, however, significantly promoted α‐Syn fibrillation, with a more than a 20‐fold reduction of lag times before fibrillation onset. When α‐Syn bilayer interactions were analysed at an individual residue level by solution‐state NMR, we observed two different effects of cholesterol. In nanodiscs made of DOPC, the addition of cholesterol modulated the NAC part of α‐Syn, leading to stronger interaction of this region with the lipid bilayer. In contrast, in the nanodiscs comprising DOPC, DOPE and DOPG, the NAC part was mostly unaffected by the presence of cholesterol, while the binding of the N and the C termini was both inhibited.
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| 20. |
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| 21. |
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| 22. |
- Karamanos, Nikos K., et al.
(författare)
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A guide to the composition and functions of the extracellular matrix
- 2021
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 288:24, s. 6850-6912
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular matrix (ECM) is a dynamic 3-dimensional network of macromolecules that provides structural support for the cells and tissues. Accumulated knowledge clearly demonstrated over the last decade that ECM plays key regulatory roles since it orchestrates cell signaling, functions, properties and morphology. Extracellularly secreted as well as cell-bound factors are among the major members of the ECM family. Proteins/glycoproteins, such as collagens, elastin, laminins and tenascins, proteoglycans and glycosaminoglycans, hyaluronan, and their cell receptors such as CD44 and integrins, responsible for cell adhesion, comprise a well-organized functional network with significant roles in health and disease. On the other hand, enzymes such as matrix metalloproteinases and specific glycosidases including heparanase and hyaluronidases contribute to matrix remodeling and affect human health. Several cell processes and functions, among them cell proliferation and survival, migration, differentiation, autophagy, angiogenesis, and immunity regulation are affected by certain matrix components. Structural alterations have been also well associated with disease progression. This guide on the composition and functions of the ECM gives a broad overview of the matrisome, the major ECM macromolecules, and their interaction networks within the ECM and with the cell surface, summarizes their main structural features and their roles in tissue organization and cell functions, and emphasizes the importance of specific ECM constituents in disease development and progression as well as the advances in molecular targeting of ECM to design new therapeutic strategies.
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| 23. |
- King, Katharine
(författare)
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Multiple enzymatic approaches to hydrolysis of fungal beta-glucans by the soil bacterium Chitinophaga pinensis
- 2023
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Ingår i: The Febs Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 290, s. 2909-2922
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Tidskriftsartikel (refereegranskat)abstract
- The genome of the soil Bacteroidota Chitinophaga pinensis encodes a large number of glycoside hydrolases (GHs) with noteworthy features and potentially novel functions. Several are predicted to be active on polysaccharide components of fungal and oomycete cell walls, such as chitin, beta-1,3-glucan and beta-1,6-glucan. While several fungal beta-1,6-glucanase enzymes are known, relatively few bacterial examples have been characterised to date. We have previously demonstrated that C. pinensis shows strong growth using beta-1,6-glucan as the sole carbon source, with the efficient release of oligosaccharides from the polymer. We here characterise the capacity of the C. pinensis secretome to hydrolyse the beta-1,6-glucan pustulan and describe three distinct enzymes encoded by its genome, all of which show different levels of beta-1,6-glucanase activity and which are classified into different GH families. Our data show that C. pinensis has multiple tools to deconstruct pustulan, allowing the species' broad utility of this substrate, with potential implications for bacterial biocontrol of pathogens via cell wall disruption. Oligosaccharides derived from fungal beta-1,6-glucans are valuable in biomedical research and drug synthesis, and these enzymes could be useful tools for releasing such molecules from microbial biomass, an underexploited source of complex carbohydrates.
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| 24. |
- Košenina, Sara, 1993-, et al.
(författare)
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The cryo-EM structure of the BoNT/Wo-NTNH complex reveals two immunoglobulin-like domains
- 2024
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Ingår i: The FEBS Journal. - 1742-464X .- 1742-4658. ; 291:4, s. 676-689
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Tidskriftsartikel (refereegranskat)abstract
- The botulinum neurotoxin-like toxin from Weissella oryzae (BoNT/Wo) is one of the BoNT-like toxins recently identified outside of the Clostridium genus. We show that, like the canonical BoNTs, BoNT/Wo forms a complex with its non-toxic non-hemagglutinin (NTNH) partner, which in traditional BoNT serotypes protects the toxin from proteases and the acidic environment of the hosts' guts. We here report the cryo-EM structure of the 300 kDa BoNT/Wo-NTNH/Wo complex together with pH stability studies of the complex. The structure reveals molecular details of the toxin's interactions with its protective partner. The overall structural arrangement is similar to other reported BoNT-NTNH complexes, but NTNH/Wo uniquely contains two extra bacterial immunoglobulin-like (Big) domains on the C-terminus. Although the function of these Big domains is unknown, they are structurally most similar to bacterial proteins involved in adhesion to host cells. In addition, the BoNT/Wo protease domain contains an internal disulfide bond not seen in other BoNTs. Mass photometry analysis revealed that the BoNT/Wo-NTNH/Wo complex is stable under acidic conditions and may dissociate at neutral to basic pH. These findings established that BoNT/Wo-NTNH/Wo shares the general fold of canonical BoNT–NTNH complexes. The presence of unique structural features suggests that it may have an alternative mode of activation, translocation and recognition of host cells, raising interesting questions about the activity and the mechanism of action of BoNT/Wo as well as about its target environment, receptors and substrates.
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| 25. |
- Krintel, Christian, et al.
(författare)
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Binding of a negative allosteric modulator and competitive antagonist can occur simultaneously at the ionotropic glutamate receptor GluA2
- 2021
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 288:3, s. 995-1007
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Tidskriftsartikel (refereegranskat)abstract
- Ionotropic glutamate receptors are ligand-gated ion channels governing neurotransmission in the central nervous system. Three major types of antagonists are known for the AMPA-type receptor GluA2: competitive, non-competitive (i.e. negative allosteric modulators; NAMs) used for treatment of epilepsy, and uncompetitive antagonists. We here report a 4.65 Å resolution X-ray structure of GluA2, revealing that four molecules of the competitive antagonist ZK200775 and four molecules of the NAM GYKI53655 are capable of binding at the same time. Using negative stain electron microscopy, we show that GYKI53655 alone or ZK200775/GYKI53655 in combination predominantly result in compact receptor forms. The agonist AMPA provides a mixed population of compact and bulgy shapes of GluA2 not impacted by addition of GYKI53655. Taken together, this suggests that the two different mechanisms of antagonism that lead to channel closure are independent and that the distribution between bulgy and compact receptors primarily depends on the ligand bound in the glutamate binding site.
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| 26. |
- Liebscher, I, et al.
(författare)
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A guide to adhesion GPCR research
- 2022
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Ingår i: The FEBS journal. - : Wiley. - 1742-4658 .- 1742-464X. ; 289:24, s. 7610-7630
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Tidskriftsartikel (refereegranskat)
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| 27. |
- Liu, Huan, et al.
(författare)
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The first human induced pluripotent stem cell line of Kashin–Beck disease reveals involvement of heparan sulfate proteoglycan biosynthesis and PPAR pathway
- 2022
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 289:1, s. 279-293
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Kashin-Beck disease (KBD) is an endemic osteochondropathy. Due to a lack of suitable animal or cellular disease models, the research progress on KBD has been limited. Our goal was to establish the first disease-specific human induced pluripotent stem cells (hiPSCs) cellular disease model of KBD, and to explore its etiology and pathogenesis exploiting transcriptome sequencing.METHODS: HiPSCs were reprogrammed from dermal fibroblasts of two KBD and one healthy control donors via integration-free vectors. Subsequently, hiPSCs were differentiated into chondrocytes through three-week culture. Gene expression profiles in KBD, normal primary chondrocytes and hiPSC-derived chondrocytes were defined by RNA sequencing. A Venn diagram was constructed to show the number of shared differentially expressed genes (DEGs) between KBD and normal. Gene oncology and Kyoto Encyclopedia of Genes and Genomes annotations were performed, and six DEGs were further validated in other individuals by real-time quantitative reverse transcription PCR (RT-qPCR).RESULTS: KBD cellular disease models were successfully established by generation of hiPSC lines. Seventeen consistent and significant DEGs present in all compared groups (KBD and normal) were identified. RT-qPCR validation gave consistent results with the sequencing data. Glycosaminoglycan biosynthesis-heparan sulfate/heparin, PPAR signaling pathway and cell adhesion molecules (CAMs) pathways were identified to be significantly altered in KBD.CONCLUSION: Differentiated chondrocytes deriving from KBD-origin hiPSCs provide the first cellular disease model for etiological studies of KBD. This study also provides new sights into the pathogenesis and etiology of KBD and is likely to inform the development of targeted therapeutics for its treatment.
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| 28. |
- Lu, Zijia, et al.
(författare)
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Multiple enzymatic approaches to hydrolysis of fungal β-glucans by the soil bacterium Chitinophaga pinensis
- 2023
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 290:11, s. 2909-2922
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Tidskriftsartikel (refereegranskat)abstract
- The genome of the soil Bacteroidota Chitinophaga pinensis encodes a large number of glycoside hydrolases (GHs) with noteworthy features and potentially novel functions. Several are predicted to be active on polysaccharide components of fungal and oomycete cell walls, such as chitin, β-1,3-glucan and β-1,6-glucan. While several fungal β-1,6-glucanase enzymes are known, relatively few bacterial examples have been characterised to date. We have previously demonstrated that C. pinensis shows strong growth using β-1,6-glucan as the sole carbon source, with the efficient release of oligosaccharides from the polymer. We here characterise the capacity of the C. pinensis secretome to hydrolyse the β-1,6-glucan pustulan and describe three distinct enzymes encoded by its genome, all of which show different levels of β-1,6-glucanase activity and which are classified into different GH families. Our data show that C. pinensis has multiple tools to deconstruct pustulan, allowing the species' broad utility of this substrate, with potential implications for bacterial biocontrol of pathogens via cell wall disruption. Oligosaccharides derived from fungal β-1,6-glucans are valuable in biomedical research and drug synthesis, and these enzymes could be useful tools for releasing such molecules from microbial biomass, an underexploited source of complex carbohydrates.
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| 29. |
- Lüscher, Bernhard, et al.
(författare)
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ADP-ribosyltransferases, an update on function and nomenclature
- 2022
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 289:23, s. 7399-7410
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Tidskriftsartikel (refereegranskat)abstract
- ADP-ribosylation, a modification of proteins, nucleic acids, and metabolites, confers broad functions, including roles in stress responses elicited, for example, by DNA damage and viral infection and is involved in intra- and extracellular signaling, chromatin and transcriptional regulation, protein biosynthesis, and cell death. ADP-ribosylation is catalyzed by ADP-ribosyltransferases (ARTs), which transfer ADP-ribose from NAD+ onto substrates. The modification, which occurs as mono- or poly-ADP-ribosylation, is reversible due to the action of different ADP-ribosylhydrolases. Importantly, inhibitors of ARTs are approved or are being developed for clinical use. Moreover, ADP-ribosylhydrolases are being assessed as therapeutic targets, foremost as antiviral drugs and for oncological indications. Due to the development of novel reagents and major technological advances that allow the study of ADP-ribosylation in unprecedented detail, an increasing number of cellular processes and pathways are being identified that are regulated by ADP-ribosylation. In addition, characterization of biochemical and structural aspects of the ARTs and their catalytic activities have expanded our understanding of this protein family. This increased knowledge requires that a common nomenclature be used to describe the relevant enzymes. Therefore, in this viewpoint, we propose an updated and broadly supported nomenclature for mammalian ARTs that will facilitate future discussions when addressing the biochemistry and biology of ADP-ribosylation. This is combined with a brief description of the main functions of mammalian ARTs to illustrate the increasing diversity of mono- and poly-ADP-ribose mediated cellular processes.
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| 30. |
- Matuleviciute, R, et al.
(författare)
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Oxygen regulation of TET enzymes
- 2021
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Ingår i: The FEBS journal. - : Wiley. - 1742-4658 .- 1742-464X. ; 288:24, s. 7143-7161
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Tidskriftsartikel (refereegranskat)
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| 31. |
- Maurer, S., et al.
(författare)
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The colorful versatility of adipocytes: white-to-brown transdifferentiation and its therapeutic potential in man
- 2021
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Ingår i: FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 288:12, s. 3628-3646
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Tidskriftsartikel (refereegranskat)abstract
- Brown and brite adipocytes contribute to energy expenditure through nonshivering thermogenesis. Though these cell types are thought to arise primarily from thede novodifferentiation of precursor cells, their abundance is also controlled through the transdifferentiation of mature white adipocytes. Here, we review recent advances in our understanding of the regulation of white-to-brown transdifferentiation, as well as the conversion of brown and brite adipocytes to dormant, white-like fat cells. Converting mature white adipocytes into brite cells or reactivating dormant brown and brite adipocytes has emerged as a strategy to ameliorate human metabolic disorders. We analyze the evidence of learning from mice and how they translate to humans to ultimately scrutinize the relevance of this concept. Moreover, we estimate that converting a small percentage of existing white fat mass in obese subjects into active brite adipocytes could be sufficient to achieve meaningful benefits in metabolism. In conclusion, novel browning agents have to be identified before adipocyte transdifferentiation can be realized as a safe and efficacious therapy in man.
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| 32. |
- Noborn, Fredrik, et al.
(författare)
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Role of neurexin heparan sulfate in the molecular assembly of synapses - Expanding the neurexin code?
- 2023
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Ingår i: Febs Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 290:3, s. 252-265
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Tidskriftsartikel (refereegranskat)abstract
- Synapses are the minimal information processing units of the brain and come in many flavors across distinct circuits. The shape and properties of a synapse depend on its molecular organisation, which is thought to largely depend on interactions between cell adhesion molecules across the synaptic cleft. An established example is that of presynaptic neurexins and their interactions with structurally diverse postsynaptic ligands: the diversity of neurexin isoforms that arise from alternative promoters and alternative splicing specify synaptic properties by dictating ligand preference. The recent finding that a majority of neurexin isoforms exist as proteoglycans with a single heparan sulfate (HS) polysaccharide adds to this complexity. Sequence motifs within the HS polysaccharide may differ between neuronal cell types to contribute specificity to its interactions, thereby expanding the coding capacity of neurexin diversity. However, an expanding number of HS-binding proteins have been found capable to recruit neurexins via the HS chain, challenging the concept of a code provided by neurexin splice isoforms. Here we discuss the possible roles of the neurexin HS in light of what is known from other HS-protein interactions, and propose a model for how the neurexin HS polysaccharide may contribute to synaptic assembly. We also discuss how the neurexin HS may be regulated by co-secreted carbonic anhydrase-related and FAM19A proteins, and highlight some key issues that should be resolved to advance the field.
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| 33. |
- Olson, William J., et al.
(författare)
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Regulation of the germinal center response by nuclear receptors and implications for autoimmune diseases
- 2020
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Ingår i: The FEBS Journal. - : WILEY. - 1742-464X .- 1742-4658. ; 287:14, s. 2866-2890
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Forskningsöversikt (refereegranskat)abstract
- The immune system plays an essential role in protecting the host from infectious diseases and cancer. Notably, B and T lymphocytes from the adaptive arm of the immune system can co-operate to form long-lived antibody responses and are therefore the main target in vaccination approaches. Nevertheless, protective immune responses must be tightly regulated to avoid hyper-responsiveness and responses against self that can result in autoimmunity. Nuclear receptors (NRs) are perfectly adapted to rapidly alter transcriptional cellular responses to altered environmental settings. Their functional role is associated with both immune deficiencies and autoimmunity. Despite extensive linking of nuclear receptor function with specific CD4 T helper subsets, research on the functional roles and mechanisms of specific NRs in CD4 follicular T helper cells (Tfh) and germinal center (GC) B cells during the germinal center reaction is just emerging. We review recent advances in our understanding of NR regulation in specific cell types of the GC response and discuss their implications for autoimmune diseases such as systemic lupus erythematosus (SLE).
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| 34. |
- Partel, Gabriele, 1988-, et al.
(författare)
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Spage2vec : Unsupervised representation of localized spatial gene expression signatures
- 2021
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 288:6, s. 1859-1870
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Tidskriftsartikel (refereegranskat)abstract
- Investigations of spatial cellular composition of tissue architectures revealed by multiplexed in situ RNA detection often rely on inaccurate cell segmentation or prior biological knowledge from complementary single cell sequencing experiments. Here we present spage2vec, an unsupervised segmentation free approach for decrypting the spatial transcriptomic heterogeneity of complex tissues at subcellular resolution. Spage2vec represents the spatial transcriptomic landscape of tissue samples as a graph and leverages a powerful machine learning graph representation technique to create a lower dimensional representation of local spatial gene expression. We apply spage2vec to mouse brain data from three different in situ transcriptomic assays and to a spatial gene expression dataset consisting of hundreds of individual cells. We show that learned representations encode meaningful biological spatial information of re-occuring localized gene expression signatures involved in cellular and subcellular processes.
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| 35. |
- Pavlović, Natasa, et al.
(författare)
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Targeting ER stress in the hepatic tumor microenvironment
- 2022
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 289:22, s. 7163-7176
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Forskningsöversikt (refereegranskat)abstract
- Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. It currently ranks as one of the most aggressive and deadly cancers worldwide, with an increasing mortality rate and limited treatment options. An important hallmark of liver pathologies, such as liver fibrosis and HCC, is the accumulation of misfolded and unfolded proteins in the lumen of the endoplasmic reticulum (ER), which induces ER stress and leads to the activation of the unfolded protein response (UPR). Upon accumulation of misfolded proteins, ER stress is sensed through three transmembrane proteins, IRE1α, PERK, and ATF6, which trigger the UPR to either alleviate ER stress or induce apoptosis. Increased expression of ER stress markers has been widely shown to correlate with fibrosis, inflammation, drug resistance, and overall HCC aggressiveness, as well as poor patient prognosis. While preclinical in vivo cancer models and in vitro approaches have shown promising results by pharmacologically targeting ER stress mediators, the major challenge of this therapeutic strategy lies in specifically and effectively targeting ER stress in HCC. Furthermore, both ER stress inducers and inhibitors have been shown to ameliorate HCC progression, adding to the complexity of targeting ER stress players as an anticancer strategy. More studies are needed to better understand the dual role and molecular background of ER stress in HCC, as well as its therapeutic potential for patients with liver cancer.
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| 36. |
- Risso, V., et al.
(författare)
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Metalloprotease-mediated cleavage of CD95 ligand
- 2023
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Ingår i: FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 290:12, s. 3145-64
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Tidskriftsartikel (refereegranskat)abstract
- CD95 is a member of the TNF receptor superfamily that is ubiquitously expressed in healthy and pathological tissues. Stimulation of CD95 by its physiological ligand CD95L induces its oligomerization leading in turn to the transduction of either apoptotic or nonapoptotic signals. CD95L can exist as both membrane-anchored and soluble forms (sCD95L), the latter resulting from the proteolytic cleavage of the former. Candidate proteases able to achieve CD95L cleavage were identified as matrix metalloproteases (MMP) due to their demonstrated ability to cleave other TNF superfamily ligands. The main goal of this study was to systematically identify the MMP family members capable of cleaving CD95L and subsequently determine the corresponding cleavage sites. By using different orthogonal biochemical approaches and combining them with molecular modelling, we confirmed data from the literature regarding CD95L cleavage by MMP-3 and MMP-7. Moreover, we found that MMP-2 and MMP-12 can cleave CD95L and characterized their resulting cleavage sites. This study provides a systematic approach to analyse the cleavage of CD95L, which until now had only been poorly described.
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| 37. |
- Sanches, Jose Marcos, et al.
(författare)
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Pathophysiology of type 2 diabetes and the impact of altered metabolic interorgan crosstalk
- 2023
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 290:3, s. 620-648
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Forskningsöversikt (refereegranskat)abstract
- Diabetes is a complex and multifactorial disease that affects millions of people worldwide, reducing the quality of life significantly, and results in grave consequences for our health care system. In type 2 diabetes (T2D), the lack of β-cell compensatory mechanisms overcoming peripherally developed insulin resistance is a paramount factor leading to disturbed blood glucose levels and lipid metabolism. Impaired β-cell functions and insulin resistance have been studied extensively resulting in a good understanding of these pathways but much less is known about interorgan crosstalk, which we define as signaling between tissues by secreted factors. Besides hormones and organokines, dysregulated blood glucose and long-lasting hyperglycemia in T2D is associated with changes in metabolism with metabolites from different tissues contributing to the development of this disease. Recent data suggest that metabolites, such as lipids including free fatty acids and amino acids, play important roles in the interorgan crosstalk during the development of T2D. In general, metabolic remodeling affects physiological homeostasis and impacts the development of T2D. Hence, we highlight the importance of metabolic interorgan crosstalk in this review to gain enhanced knowledge of the pathophysiology of T2D, which may lead to new therapeutic approaches to treat this disease.
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| 38. |
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| 39. |
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| 40. |
- Sjöström, Dick J., et al.
(författare)
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Motif-driven protein binder design towards transferrin receptor helical domain
- 2022
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 289:10, s. 2935-2947
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Tidskriftsartikel (refereegranskat)abstract
- Human transferrin receptor 1 (TfR) is necessary for the delivery of the iron carrier protein transferrin into cells and can be utilized for targeted delivery across cellular membranes. Binding of transferrin to the receptor is regulated by hereditary hemochromatosis protein (HFE), an iron regulatory protein that partly shares a binding site with transferrin on TfR. Here, we derived essential binding interactions from HFE and computationally grafted these into a library of small protein scaffolds. One of the designed proteins, TB08, was further optimized computationally and experimentally to identify variants with improved binding to TfR. The optimized variant, TB08 S3.1, expressed well in the E. coli expression system and had an affinity to TfR in the low micromolar range, K-d approximate to 1 mu m, as determined by surface plasmon resonance. A binding competition assay with transferrin further confirmed the interaction of the evolved variant to TfR at the shared binding surface. Additionally, the GFP-tagged evolved variant of TB08 demonstrated cellular internalization as determined by fluorescent and confocal microscopy in HeLa cells. The designed protein is small, allows for robust cargo tagging, and interacts specifically with TfR, thus making it a valuable tool for the characterization of TfR-mediated cellular transport mechanisms and for the assessment of engineering strategies for cargo delivery across cell membranes.
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| 41. |
- Springstein, Benjamin L., et al.
(författare)
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Two novel heteropolymer‐forming proteins maintain the multicellular shape of the cyanobacterium Anabaena sp. PCC 7120
- 2020
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 288:10, s. 3197-3216
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Tidskriftsartikel (refereegranskat)abstract
- olymerizing and filament-forming proteins are instrumental for numerous cellular processes such as cell division and growth. Their function in stabilization and localization of protein complexes and replicons is achieved by a filamentous structure. Known filamentous proteins assemble into homopolymers consisting of single subunits – for example, MreB and FtsZ in bacteria – or heteropolymers that are composed of two subunits, for example, keratin and α/β tubulin in eukaryotes. Here, we describe two novel coiled-coil-rich proteins (CCRPs) in the filament-forming cyanobacterium Anabaena sp. PCC 7120 (hereafter Anabaena) that assemble into a heteropolymer and function in the maintenance of the Anabaena multicellular shape (termed trichome). The two CCRPs – Alr4504 and Alr4505 (named ZicK and ZacK) – are strictly interdependent for the assembly of protein filaments in vivo and polymerize nucleotide independently in vitro, similar to known intermediate filament (IF) proteins. A ΔzicKΔzacK double mutant is characterized by a zigzagged cell arrangement and hence a loss of the typical linear Anabaena trichome shape. ZicK and ZacK interact with themselves, with each other, with the elongasome protein MreB, the septal junction protein SepJ and the divisome associate septal protein SepI. Our results suggest that ZicK and ZacK function in cooperation with SepJ and MreB to stabilize the Anabaena trichome and are likely essential for the manifestation of the multicellular shape in Anabaena. Our study reveals the presence of filament-forming IF-like proteins whose function is achieved through the formation of heteropolymers in cyanobacteria.
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| 42. |
- Wegrzyn, Agnieszka B., et al.
(författare)
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Fibroblast-specific genome-scale modelling predicts an imbalance in amino acid metabolism in Refsum disease
- 2020
-
Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 287:23, s. 5096-5113
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Tidskriftsartikel (refereegranskat)abstract
- Refsum disease (RD) is an inborn error of metabolism that is characterised by a defect in peroxisomal α-oxidation of the branched-chain fatty acid phytanic acid. The disorder presents with late-onset progressive retinitis pigmentosa and polyneuropathy and can be diagnosed biochemically by elevated levels of phytanate in plasma and tissues of patients. To date, no cure exists for RD, but phytanate levels in patients can be reduced by plasmapheresis and a strict diet. In this study, we reconstructed a fibroblast-specific genome-scale model based on the recently published, FAD-curated model, based on Recon3D reconstruction. We used transcriptomics (available via GEO database with identifier GSE138379), metabolomics and proteomics (available via ProteomeXchange with identifier PXD015518) data, which we obtained from healthy controls and RD patient fibroblasts incubated with phytol, a precursor of phytanic acid. Our model correctly represents the metabolism of phytanate and displays fibroblast-specific metabolic functions. Using this model, we investigated the metabolic phenotype of RD at the genome scale, and we studied the effect of phytanate on cell metabolism. We identified 53 metabolites that were predicted to discriminate between healthy and RD patients, several of which with a link to amino acid metabolism. Ultimately, these insights in metabolic changes may provide leads for pathophysiology and therapy. Databases: Transcriptomics data are available via GEO database with identifier GSE138379, and proteomics data are available via ProteomeXchange with identifier PXD015518.
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| 43. |
- Zavarise, Alberto, et al.
(författare)
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Structures of lactaldehyde reductase, FucO, link enzyme activity to hydrogen bond networks and conformational dynamics
- 2023
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Ingår i: The FEBS Journal. - : John Wiley & Sons. - 1742-464X .- 1742-4658. ; 290:2, s. 465-481
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Tidskriftsartikel (refereegranskat)abstract
- A group-III iron containing 1,2-propanediol oxidoreductase, FucO, (also known as lactaldehyde reductase) from Escherichia coli was examined regarding its structure–dynamics–function relationships in the catalysis of the NADH-dependent reduction of (2S)-lactaldehyde. Crystal structures of FucO variants in the presence or absence of cofactors have been determined, illustrating large domain movements between the apo and holo enzyme structures. Different structures of FucO variants co-crystallized with NAD+ or NADH together with substrate further suggest dynamic properties of the nicotinamide moiety of the coenzyme that are important for the reaction mechanism. Modelling of the native substrate (2S)-lactaldehyde into the active site can explain the stereoselectivity exhibited by the enzyme, with a critical hydrogen bond interaction between the (2S)-hydroxyl and the side-chain of N151, as well as the previously experimentally demonstrated pro-(R) selectivity in hydride transfer from NADH to the aldehydic carbon. Furthermore, the deuterium kinetic isotope effect of hydride transfer suggests that reduction chemistry is the main rate-limiting step for turnover which is not the case in FucO catalysed alcohol oxidation. We further propose that a water molecule in the active site – hydrogen bonded to a conserved histidine (H267) and the 2′-hydroxyl of the coenzyme ribose – functions as a catalytic proton donor in the protonation of the product alcohol. A hydrogen bond network of water molecules and the side-chains of amino acid residues D360 and H267 links bulk solvent to this proposed catalytic water molecule.
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| 44. |
- Zhao, Li Na, et al.
(författare)
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Pairing structural reconstruction with catalytic competence to evaluate the mechanisms of key enzymes in the folate-mediated one-carbon pathway
- 2023
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 290:9, s. 2279-2291
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Forskningsöversikt (refereegranskat)abstract
- Mammalian metabolism comprises a series of interlinking pathways that include two major cycles: the folate and methionine cycles. The folate-mediated metabolic cycle uses several oxidation states of tetrahydrofolate to carry activated one-carbon units to be readily used and interconverted within the cell, which are required for nucleotide synthesis, methylation and metabolism, particularly for proliferation of cancer cells. Based on the latest progress in genome-wide CRISPR loss-of-function viability screening of 789 cell lines, we focus on the most cancer dependent enzymes in this pathway, especially those that are hyperactivated in cancer, to provide new insight into the chemical basis for cancer drug development. Since the complete 3D structure of several of these enzymes in their active form are not available, we used homology modeling integrated with the interpretation of the reaction mechanism, and have reconstructed the most likely scenario for the reactions to take place paired with their catalytic cycle that provides a testable framework for this pathway.
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| 45. |
- Ahmadpour, Doryaneh, 1973, et al.
(författare)
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Syntaxin 5-dependent phosphorylation of the small heat shock protein Hsp42 and its role in protein quality control
- 2023
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Ingår i: Febs Journal. - 1742-464X. ; 290:19, s. 4744-4761
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Tidskriftsartikel (refereegranskat)abstract
- The small heat shock protein Hsp42 and the t-SNARE protein Sed5 have central roles in the sequestration of misfolded proteins into insoluble protein deposits in the yeast Saccharomyces cerevisiae. However, whether these proteins/processes interact in protein quality control (PQC) is not known. Here, we show that Sed5 and anterograde trafficking modulate phosphorylation of Hsp42 partially via the MAPK kinase Hog1. Such phosphorylation, specifically at residue S215, abrogated the co-localization of Hsp42 with the Hsp104 disaggregase, aggregate clearance, chaperone activity, and sequestration of aggregates to IPOD and mitochondria. Furthermore, we found that Hsp42 is hyperphosphorylated in old cells leading to a drastic failure in disaggregation. Old cells also displayed a retarded anterograde trafficking, which, together with slow aggregate clearance and hyperphosphorylation of Hsp42, could be counteracted by Sed5 overproduction. We hypothesize that the breakdown of proper PQC during yeast aging may, in part, be due to a retarded anterograde trafficking leading to hyperphosphorylation of Hsp42.
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