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| 2. |
- Lundgren, Jolanta L, et al.
(författare)
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ADAM10 and BACE1 are localized to synaptic vesicles.
- 2015
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 135:3, s. 606-615
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Tidskriftsartikel (refereegranskat)abstract
- Synaptic degeneration and accumulation of the neurotoxic amyloid β-peptide (Aβ) in the brain are hallmarks of Alzheimer disease. Aβ is produced by sequential cleavage of its precursor protein, APP, by the β-secretase BACE1 and γ-secretase. However, Aβ generation is precluded if APP is cleaved by the α-secretase ADAM10 instead of BACE1. We have previously shown that Aβ can be produced locally at the synapse. To study the synaptic localization of the APP processing enzymes we used western blotting to demonstrate that, compared to total brain homogenate, ADAM10 and BACE1 were greatly enriched in synaptic vesicles isolated from rat brain using controlled-pore glass chromatography, whereas Presenilin1 was the only enriched component of the γ-secretase complex. Moreover, we detected ADAM10 activity in synaptic vesicles and enrichment of the intermediate APP-C-terminal fractions (APP-CTFs). We confirmed the western blotting findings using in situ proximity ligation assay to demonstrate close proximity of ADAM10 and BACE1 with the synaptic vesicle marker synaptophysin in intact mouse primary hippocampal neurons. In contrast, only sparse co-localization of active γ-secretase and synaptophysin was detected. These results indicate that the first step of APP processing occurs in synaptic vesicles whereas the final step is more likely to take place elsewhere. This article is protected by copyright. All rights reserved.
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| 3. |
- Matt, C. E., et al.
(författare)
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Direct observation of orbital hybridisation in a cuprate superconductor
- 2018
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The minimal ingredients to explain the essential physics of layered copper-oxide (cuprates) materials remains heavily debated. Effective low-energy single-band models of the copper-oxygen orbitals are widely used because there exists no strong experimental evidence supporting multi-band structures. Here, we report angle-resolved photoelectron spectroscopy experiments on La-based cuprates that provide direct observation of a two-band structure. This electronic structure, qualitatively consistent with density functional theory, is parametrised by a two-orbital (d(x2-y2) and d(z2)) tight-binding model. We quantify the orbital hybridisation which provides an explanation for the Fermi surface topology and the proximity of the van-Hove singularity to the Fermi level. Our analysis leads to a unification of electronic hopping parameters for single-layer cuprates and we conclude that hybridisation, restraining d-wave pairing, is an important optimisation element for superconductivity.
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| 4. |
- Matt, C. E., et al.
(författare)
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Electron scattering, charge order, and pseudogap physics in La1.6-xNd0.4SrxCuO4 : An angle-resolved photoemission spectroscopy study
- 2015
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 92:13
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Tidskriftsartikel (refereegranskat)abstract
- We report an angle-resolved photoemission study of the charge stripe ordered La1.6-xNd0.4SrxCuO4 (Nd-LSCO) system. A comparative and quantitative line-shape analysis is presented as the system evolves from the overdoped regime into the charge ordered phase. On the overdoped side (x = 0.20), a normal-state antinodal spectral gap opens upon cooling below 80 K. In this process, spectral weight is preserved but redistributed to larger energies. A correlation between this spectral gap and electron scattering is found. A different line shape is observed in the antinodal region of charge ordered Nd-LSCO x = 1/8. Significant low-energy spectral weight appears to be lost. These observations are discussed in terms of spectral-weight redistribution and gapping originating from charge stripe ordering.
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| 5. |
- Tjernberg, L. O., et al.
(författare)
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Transmissible amyloid
- 2016
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 280:2, s. 153-163
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Forskningsöversikt (refereegranskat)abstract
- There are around 30 human diseases associated with protein misfolding and amyloid formation, each one caused by a certain protein or peptide. Many of these diseases are lethal and together they pose an enormous burden to society. The prion protein has attracted particular interest as being shown to be the pathogenic agent in transmissible diseases such as kuru, Creutzfeldt-Jakob disease and bovine spongiform encephalopathy. Whether similar transmission could occur also in other amyloidoses such as Alzheimer's disease, Parkinson's disease and serum amyloid A amyloidosis is a matter of intense research and debate. Furthermore, it has been suggested that novel biomaterials such as artificial spider silk are potentially amyloidogenic. Here, we provide a brief introduction to amyloid, prions and other proteins involved in amyloid disease and review recent evidence for their potential transmission. We discuss the similarities and differences between amyloid and silk, as well as the potential hazards associated with protein-based biomaterials. Read more articles from the symposium: Amyloid - a multifaceted player in human health and disease.
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| 6. |
- Östlin, A., et al.
(författare)
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Electronic structure of palladium in the presence of many-body effects
- 2016
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 93:15
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Tidskriftsartikel (refereegranskat)abstract
- Including on-site electronic interactions described by the multiorbital Hubbard model we study the correlation effects in the electronic structure of bulk palladium. We use a combined density functional and dynamical mean-field theory, LDA+DMFT, based on the fluctuation exchange approximation. The agreement between the experimentally determined and the theoretical lattice constant and bulk modulus is improved when correlation effects are included. It is found that correlations modify the Fermi surface around the neck at the L point while the Fermi surface tube structures show little correlation effects. At the same time we discuss the possibility of satellite formation in the high-energy binding region. Spectral functions obtained within the LDA+DMFT and GW methods are compared to discuss nonlocal correlation effects. For relatively weak local Coulomb interaction and Hund's exchange coupling the LDA+DMFT spectra show no major difference in comparison to GW.
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