| 1. |
- Karlsson, Oskar, et al.
(författare)
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MALDI imaging delineates hippocampal glycosphingolipid changes associated with neurotoxin induced proteopathy following neonatal BMAA exposure.
- 2017
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002 .- 1878-2434. ; 1865:7, s. 740-746
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Tidskriftsartikel (refereegranskat)abstract
- The environmental toxin β-N-methylamino-L-alanine (BMAA) has been proposed to contribute to neurodegenerative diseases. We have previously shown that neonatal exposure to BMAA results in dose-dependent cognitive impairments, proteomic alterations and progressive neurodegeneration in the hippocampus of adult rats. A high BMAA dose (460mg/kg) also induced intracellular fibril formation, increased protein ubiquitination and enrichment of proteins important for lipid transport and metabolism. The aim of this study was therefore to elucidate the role of neuronal lipids in BMAA-induced neurodegeneration. By using matrix assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS), we characterized the spatial lipid profile in the hippocampus of six month-old rats that were treated neonatally (postnatal days 9-10) with 460mg/kg BMAA. Multivariate statistical analysis revealed long-term changes in distinct ganglioside species (GM, GD, GT) in the dentate gyrus. These changes could be a consequence of direct effects on ganglioside biosynthesis through the b-series (GM3-GD3-GD2-GD1b-GT1b) and may be linked to astrogliosis. Complementary immunohistochemistry experiments towards GFAP and S100β further verified the role of increased astrocyte activity in BMAA-induced brain damage. This highlights the potential of imaging MS for probing chemical changes associated with neuropathological mechanisms in situ. This article is part of a Special Issue entitled: MALDI Imaging, edited by Dr. Corinna Henkel and Prof. Peter Hoffmann.
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| 2. |
- Ahmad, Shabbir, et al.
(författare)
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Trimeric microsomal glutathione transferase 2 displays one third of the sites reactivity
- 2015
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1570-9639 .- 1878-1454. ; 1854:1010 Pt A, s. 1365-1371
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Tidskriftsartikel (refereegranskat)abstract
- Human microsomal glutathione transferase 2 (MGST2) is a trimeric integral membrane protein that belongs to the membrane-associated proteins in eicosanoid and glutathione metabolism (MAPEG) family. The mammalian MAPEG family consists of six members where four have been structurally determined. MGST2 activates glutathione to form a thiolate that is crucial for GSH peroxidase activity and GSH conjugation reactions with electrophilic substrates, such as 1-chloro-2,4-dinitrobenzene (CDNB). Several studies have shown that MGST2 is able to catalyze a GSH conjugation reaction with the epoxide LTA(4) forming the pro-inflammatory LTC4. Unlike its closest homologue leukotriene C-4 synthase (LTC4S), MGST2 appears to activate its substrate GSH using only one of the three potential active sites [Ahmad S, et al. (2013) Biochemistry. 52, 1755-1764]. In order to demonstrate and detail the mechanism of one-third of the sites reactivity of MGST2, we have determined the enzyme oligomeric state, by Blue native PAGE and Differential Scanning Calorimetry, as well as the stoichiometty of substrate and substrate analog inhibitor binding to MGST2, using equilibrium dialysis and Isothermal Titration Calorimetry, respectively. Global simulations were used to fit kinetic data to determine the catalytic mechanism of MGST2 with GSH and CDNB (1-chloro-2,4-dinitrobenzene) as substrates. The best fit was observed with 1/3 of the sites catalysis as compared with a simulation where all three sites were active. In contrast to LTC4S, MGST2 displays a 1/3 the sites reactivity, a mechanism shared with the more distant family member MGST1 and recently suggested also for microsomal prostaglandin E synthase-1.
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| 3. |
- Cordeiro, Yraima, et al.
(författare)
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Modulation of p53 and prion protein aggregation by RNA
- 2019
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1570-9639 .- 1878-1454. ; 1867:10, s. 933-940
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Forskningsöversikt (refereegranskat)abstract
- Several RNA-binding proteins undergo reversible liquid-liquid phase transitions, which, in pathological conditions, might evolve into transitions to solid-state phases, giving rise to amyloid structures. Amyloidogenic and prion-like proteins, such as the tumor suppressor protein p53 and the mammalian prion protein (PrP), bind RNAs specifically or nonspecifically, resulting in changes in their propensity to undergo aggregation. Mutant p53 aggregation seems to play a crucial role in cancer through loss of function, negative dominance and gain of function. PrP conversion modulated by RNA results in highly toxic aggregates. Here, we review data on the modulatory action of RNAs on the aggregation of both proteins.
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| 4. |
- Hanrieder, Jörg, 1980, et al.
(författare)
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Spatial neuroproteomics using imaging mass spectrometry
- 2015
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1878-1454 .- 1570-9639. ; 1854:7, s. 718-731
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Forskningsöversikt (refereegranskat)abstract
- The nervous system constitutes arguably the most complicated and least understood cellular network in the human body. This consequently manifests itself in the fact that the molecular bases of neurodegenerative diseases remain unknown. The limited understanding of neurobiological mechanisms relates directly to the lack of appropriate bioanalytical technologies that allow highly resolved, sensitive, specific and comprehensive molecular imaging in complex biological matrices. Imaging mass spectrometry (IMS) is an emerging technique for molecular imaging. The technique is characterized by its high chemical specificity allowing comprehensive, spatial protein and peptide profiling in situ. Imaging MS represents therefore a powerful approach for investigation of spatio-temporal protein and peptide regulations in CNS derived tissue and cells. This review aims to provide a concise overview of major developments and applications concerning imaging mass spectrometry based protein and peptide profiling in neurobiological and biomedical research. This article is part of a Special Issue entitled: Neuroproteomics: Applications in Neuroscience and Neurology.
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| 5. |
- Michno, Wojciech, 1992, et al.
(författare)
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GM1 locates to mature amyloid structures implicating a prominent role for glycolipid-protein interactions in Alzheimer pathology
- 2019
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1878-1454 .- 1570-9639. ; 1867:5, s. 458-467
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Tidskriftsartikel (refereegranskat)abstract
- While the molecular mechanisms underlying Alzheimer's disease (AD) remain largely unknown, abnormal accumulation and deposition of beta amyloid (AD) peptides into plaques has been proposed as a critical pathological process driving disease progression. Over the last years, neuronal lipid species have been implicated in biological mechanisms underlying amyloid plaque pathology. While these processes comprise genetic features along with lipid signaling as well as direct chemical interaction of lipid species with A beta mono- and oligomers, more efforts are needed to spatially delineate the exact lipid-A beta plaque interactions in the brain. Chemical imaging using mass spectrometry (MS) allows to probe the spatial distribution of lipids and peptides in complex biological tissues comprehensively and at high molecular specificity. As different imaging mass spectrometry (IMS) modalities provide comprehensive molecular and spatial information, we here describe a multimodal ToF-SIMS- and MALDI-based IMS strategy for probing lipid and A beta peptide changes in a transgenic mouse model of AD (tgAPP(ArcSwe)). Both techniques identified a general AD-associated depletion of cortical sulfatides, while multimodal MALDI IMS revealed plaque specific lipid as well as A beta peptide isoforms. In addition, MALDI IMS analysis revealed chemical features associated with morphological heterogeneity of individual A beta deposits. Here, an altered GM1 to GM2/GM3 ganglioside metabolism was observed in the diffuse periphery of plaques but not in the core region. This was accompanied by an enrichment of A beta 1-40arc peptide at the core of these deposits. Finally, a localization of arachidonic acid (AA) conjugated phosphatidylinositols (PI) and their corresponding degradation product, lysophosphatidylinositols (LPI) to the periphery of A beta plaques was observed, indicating site specific macrophage activation and ganglioside processing.
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| 6. |
- Mishra, Rajesh, et al.
(författare)
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Impact of N-glycosylation site variants during human PrP aggregation and fibril nucleation
- 2019
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : ELSEVIER. - 1570-9639 .- 1878-1454. ; 1867:10, s. 909-921
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Tidskriftsartikel (refereegranskat)abstract
- Misfolding and aggregation of the human prion protein (PrP) cause neurodegenerative transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease. Mature native PrP is composed of 209 residues and is folded into a C-terminal globular domain (residues 125-209) comprising a small two-stranded beta-sheet and three alpha-helices. The N-terminal domain (residues 23-124) is intrinsically disordered. Expression of truncated PrP (residues 90-231) is sufficient to cause prion disease and residues 90/100-231 is comprising the amyloid-like fibril core of misfolded infectious PrP. During PrP fibril formation under native conditions in vitro, the disordered N-terminal domain slows down fibril formation likely due to a mechanism of initial aggregation forming morphologically disordered aggregates. The morphological disordered aggregate is a transient phase. Nucleation of fibrils occurs from this initial aggregate. The aggregate phase is largely circumvented by seeding with preformed PrP fibrils. In vivo PrP is N-glycosylated at positions Asn181 and Asn197. Little is known about the importance of these positions and their glycans for PrP stability, aggregation and fibril formation. We have in this study taken a step towards that goal by mutating residues 181 and 197 for cysteines to study the positional impact on these processes. We have further by organic synthetic chemistry and chemical modification generated synthetic glycosylations in these positions. Our data shows that residue 181 when mutated to a cysteine is a key residue for self -chaperoning, rendering a trap in the initial aggregate preventing conformational changes towards amyloid fibril formation. Position 197 is less involved in the aggregate trapping and is more geared towards beta-sheet structure conversion within amyloid fibrils. As expected, synthetic glycosylated 197 is less affected towards fibril formation compared to glycosylated 181. Our data are rather compatible with the parallel in-register intermolecular beta-sheet model structure of the PrP90-231 fibril and sheds light on the misfolding transitions of PrP in vitro. We hypothesize that glycosylation of position 181 is a key site for prion strain differentiation in vivo.
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| 7. |
- Nasir, Irem, 1987, et al.
(författare)
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Single-molecule fluorescence studies of intrinsically disordered proteins and liquid phase separation
- 2019
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1878-1454 .- 1570-9639. ; 1867:10, s. 980-987
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Forskningsöversikt (refereegranskat)abstract
- Intrinsically disordered proteins (IDPs) are ubiquitous in proteomes and serve in a range of cellular functions including signaling, regulation, transport and enzyme function. IDP misfunction and aggregation are also associated with several diseases including neurodegenerative diseases and cancer. During the past decade, single-molecule methods have become popular for detailed biophysical and structural studies of these complex proteins. This work has included recent applications to cellular liquid-liquid phase separation (LLPS), relevant for functional dynamics of membraneless organelles such as the nucleolus and stress granules. In this concise review, we cover the conceptual motivations for development and application of single-molecule fluorescence methods for such IDP studies. We follow with a few key examples of systems and biophysical problems that have been addressed, and conclude with thoughts for emerging and future directions.
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| 8. |
- Niedzwiecka, Anna, et al.
(författare)
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Molecular recognition of mRNA 5' cap by 3' poly(A)-specific ribonuclease (PARN) differs from interactions known for other cap-binding proteins
- 2016
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1570-9639 .- 1878-1454. ; 1864:4, s. 331-345
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Tidskriftsartikel (refereegranskat)abstract
- The mRNA 5' cap structure plays a pivotal role in coordination of eukaryotic translation and mRNA degradation. Poly(A)-specific ribonuclease (PARN) is a dimeric exoribonuclease that efficiently degrades mRNA 3' poly(A) tails while also simultaneously interacting with the mRNA 5' cap. The cap binding amplifies the processivity of PARN action. We used surface plasmon resonance kinetic analysis, quantitative equilibrium fluorescence titrations and circular dichroism to study the cap binding properties of PARN. The molecular mechanism of 5' cap recognition by PARN has been demonstrated to differ from interactions seen for other known cap-binding proteins in that: i) the auxiliary biological function of 5' cap binding by the 3' degrading enzyme is accomplished by negative cooperativity of PARN dimer subunits; ii) non-coulombic interactions are major factors in the complex formation; and iii) PARN has versatile activity toward alternative forms of the cap. These characteristics contribute to stabilization of the PARN cap complex needed for the deadenylation processivity. Our studies provide a consistent biophysical basis for elucidation of the processive mechanism of PARN-mediated 3' mRNA deadenylation and provide a new framework to interpret the role of the 5' cap in mRNA degradation.
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| 9. |
- Scirè, Andrea, et al.
(författare)
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Interaction of gamma-conglutin from Lupinus albus with model phospholipid membranes : Investigations on structure, thermal stability and oligomerization status
- 2018
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1570-9639 .- 1878-1454. ; 1866:12, s. 1242-1248
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Tidskriftsartikel (refereegranskat)abstract
- Interaction with model phospholipid membranes of lupin seed gamma-conglutin, a glycaemia-lowering protein from Lupinus albus seeds, has been studied by means of Fourier-Transform infrared spectroscopy at p(2)H 7.0 and at p(2)H 4.5. The protein maintains the same secondary structure both at p(2)H 7.0 and at p(2)H 4.5, but at p(2)H 7.0 a higher H-1/H-2 exchange was observed, indicating a greater solvent accessibility. The difference in T-m and T-D1/2 of the protein at the abovementioned p(2)H's has been calculated around 20 degrees C. Infrared measurements have been then performed in the presence of DMPG and DOPA at p(2)H 4.5. DMPG showed a little destabilizing effect while DOPA exerted a great stabilizing effect, increasing the T-m of gamma-conglutin at p(2)H 4.5 of more than 20 degrees C. Since gamma-conglutin at p(2)H 4.5 is in the monomeric form, the interaction with DOPA likely promotes the oligomerization even at p(2)H 4.5. Interaction between DMPG or DOPA and gamma-conglutin has been confirmed by turbidity experiments with DMPC:DMPG or DOPC:DOPA SUVs. Turbidity data also showed high-affinity binding of gamma-conglutin to anionic SUVs made up with DOPA. The molecular features outlined in this study are relevant to address the applicative exploitation and to delineate a deeper comprehension of the natural functional role of gamma-conglutin.
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| 10. |
- Shevchenko, Ganna, et al.
(författare)
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Neuroproteomics Tools in Clinical Practice
- 2015
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Ingår i: Biochimica et Biophysica Acta - Proteins and Proteomics. - : Elsevier BV. - 1570-9639 .- 1878-1454. ; 1854:7, s. 705-717
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Neurodegenerative disorders such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS) are characterized by neuronal impairment that leads to disease-specific changes in the neuronal proteins. The early diagnosis of these disorders is difficult, thus, the need for identifying, developing and using valid clinically applicable biomarkers that meet the criteria of precision, specificity and repeatability is very vital. The application of rapidly emerging technology such as mass spectrometry (MS) in proteomics has opened new avenues to accelerate biomarker discovery, both for diagnostic as well as for prognostic purposes. This review summarizes the most recent advances in the mass spectrometry-based neuroproteomics and analyses the current and future directions in the biomarker discovery for the neurodegenerative diseases.11 This article is part of a Special Issue entitled: Neuroproteomics: Applications in Neuroscience and Neurology.
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