| 1. |
- Backmark, Anna, 1979, et al.
(författare)
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Affinity tags can reduce merohedral twinning of membrane protein crystals
- 2008
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Ingår i: Acta Crystallographica. Section D: Biological Crystallography. - 1399-0047 .- 0907-4449. ; D64, s. 1183-1186
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a comparison of the crystal packing of three eukaryotic membrane proteins: human aquaporin 1, human aquaporin 5 and a spinach plasma membrane aquaporin. All were purified from expression constructs both with and without affinity tags. With the exception of tagged aquaporin 1, all constructs yielded crystals. Two significant effects of the affinity tags were observed: crystals containing a tag typically diffracted to lower resolution than those from constructs encoding the protein sequence alone and constructs without a tag frequently produced crystals that suffered from merohedral twinning. Twinning is a challenging crystallographic problem that can seriously hinder solution of the structure. Thus, for integral membrane proteins, the addition of an affinity tag may help to disrupt the approximate symmetry of the protein and thereby reduce or avoid merohedral twinning.
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| 2. |
- Rödström, Karin, et al.
(författare)
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Structure of the Superantigen Staphylococcal Enterotoxin B in Complex with TCR and Peptide-MHC Demonstrates Absence of TCR-Peptide Contacts.
- 2014
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Ingår i: Journal of Immunology. - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 193:4, s. 1998-2004
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Tidskriftsartikel (refereegranskat)abstract
- Superantigens are immune-stimulatory toxins produced by Staphylococcus aureus, which are able to interact with host immune receptors to induce a massive release of cytokines, causing toxic shock syndrome and possibly death. In this article, we present the x-ray structure of staphylococcal enterotoxin B (SEB) in complex with its receptors, the TCR and MHC class II, forming a ternary complex. The structure, in combination with functional analyses, clearly shows how SEB adopts a wedge-like position when binding to the β-chain of TCR, allowing for an interaction between the α-chain of TCR and MHC. Furthermore, the binding mode also circumvents contact between TCR and the peptide presented by MHC, which enables SEB to initiate a peptide-independent activation of T cells.
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| 3. |
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| 4. |
- Banke, Elin, et al.
(författare)
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Superantigen activates the gp130 receptor on adipocytes resulting in altered adipocyte metabolism.
- 2014
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Ingår i: Metabolism, Clinical and Experimental. - : Elsevier BV. - 1532-8600. ; 63:6, s. 831-840
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Tidskriftsartikel (refereegranskat)abstract
- The bacteria Staphylococcus aureus is part of the normal bacterial flora and produces a repertoire of enterotoxins which can cause food poisoning and toxic shock and might contribute to the pathogenesis of inflammatory diseases. These enterotoxins directly cross-link the T cell receptor with MHC class II, activating large amounts of T cells and are therefore called superantigens. It was recently discovered that the superantigen SEA binds to the cytokine receptor gp130. As obesity and type 2 diabetes are highly associated with inflammation of the adipose tissue and gp130 has been shown to play an important role in adipocytes, we wanted to investigate the effect of SEA on adipocyte signaling and function.
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| 5. |
- Bölenius, Karin, et al.
(författare)
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Impact of a large-scale educational intervention program on venous blood specimen collection practices
- 2013
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Ingår i: BMC Health Services Research. - : BioMed Central. - 1472-6963. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Phlebotomy performed with poor adherence to venous blood specimen collection (VBSC) guidelines jeopardizes patient safety and may lead to patient suffering and adverse events. A first questionnaire study demonstrated low compliance to VBSC guidelines, motivating an educational intervention of all phlebotomists within a county council. The aim was to evaluate the impact of a large-scale educational intervention program (EIP) on primary health care phlebotomists' adherence to VBSC guidelines. We hypothesised that the EIP would improve phlebotomists' VBSC practical performance.METHODS: The present study comprise primary health care centres (n = 61) from two county councils in northern Sweden. The final selected study group consisted of phlebotomists divided into an intervention group (n = 84) and a corresponding control group (n = 79). Both groups responded to a validated self-reported VBSC questionnaire twice. The EIP included three parts: guideline studies, an oral presentation, and an examination. Non-parametric statistics were used for comparison within and between the groups.RESULTS: Evaluating the EIP, we found significant improvements in the intervention group compared to the control group on self-reported questionnaire responses regarding information search (ES = 0.23-0.33, p < 0.001-0.003), and patient rest prior to phlebotomy (ES = 0.27, p = 0.004). Test request management, patient identity control, release of venous stasis, and test tube labelling had significantly improved in the intervention group but did not significantly differ from the control group (ES = 0.22- 0.49, p = < 0.001- 0.006). The control group showed no significant improvements at all (ES = 0--0.39, p = 0.016-0.961).CONCLUSIONS: The present study demonstrated several significant improvements on phlebotomists' adherence to VBSC practices. Still, guideline adherence improvement to several crucial phlebotomy practices is needed. We cannot conclude that the improvements are solely due to the EIP and suggest future efforts to improve VBSC. The program should provide time for reflections and discussions. Furthermore, a modular structure would allow directed educational intervention based on the specific VBSC guideline flaws existing at a specific unit. Such an approach is probably more effective at improving and sustaining adherence to VBSC guidelines than an EIP containing general pre-analytical practices.
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| 6. |
- Edvardsson, David, et al.
(författare)
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The Umeå Ageing and health research programme (U-age) : exploring person-centred care and health promoting living conditions for an ageing population
- 2016
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Ingår i: Nordic journal of nursing research. - : Sage Publications. - 2057-1585 .- 2057-1593. ; 36:3, s. 168-174
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this article is to describe the Umeå ageing and health research programme that explores person-centred care and health-promoting living conditions for an ageing population in Sweden, and to place this research programme in a national and international context of available research evidence and trends in aged care policy and practice. Contemporary trends in aged care policy includes facilitating ageing in place and providing person-centred care across home and aged care settings, despite limited evidence on how person-centred care can be operationalised in home care services and sheltered housing accommodation for older people. The Umeå ageing and health research programme consists of four research projects employing controlled, cross-sectional and longitudinal designs across ageing in place, sheltered housing, and nursing homes. The research programme is expected to provide translational knowledge on the structure, content and outcomes of person-centred care and health-promoting living conditions in home care, sheltered housing models, and nursing homes for older people and people with dementia.
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| 7. |
- Elbing, Karin, 1974, et al.
(författare)
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Towards the structure-function-specificity relationship of glucose transporters
- 2010
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Ingår i: FEBS Journal, Special issue: Abstracts of the 35th FEBS Congress, Gothenburg, Sweden, 26 June - 1 July 2010. - 1742-464X. ; 277, supplement 1, s. 209-210
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Glucose plays a central role in nutrient sensing and signalling and its uptake through facilitated diffusion is mediated by membrane associated glucose transporters, GLUT proteins in mammals and Hxt proteins in the yeast S. cerevisiae. These proteins belong to the Major Facilitator Superfamily (MFS), which is present in all studied organisms. They transport a wide range of solutes such as amino acids, sugars, nucleotides, drugs, peptides, organic and inorganic anions, metabolites, neurotransmitters, polyols etc. All MFS proteins structurally investigated have been purified from their natural sources and successful heterologous production has not yet been reported. While there is a wealth of reports in the literature on mutagenesis studies, to analyze the structure-function relationship of glucose transporters, there are no three dimensional structures available. Our research goal is to achieve a more detailed understanding of the structure-function-specificity relationship of glucose transporters. To achieve this overall goal we have successfully expressed mammalian GLUTs and yeast Hxts in yeast. Initial solubilsation trials suggest that Brij35 solubilises GLUT4. Purification and crystallization analyses of the target proteins are ongoing.
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| 8. |
- Eriksson, Stefanie, et al.
(författare)
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NMR quantification of diffusional exchange in cell suspensions with relaxation rate differences between intra and extracellular compartments
- 2017
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:5
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Tidskriftsartikel (refereegranskat)abstract
- Water transport across cell membranes can be measured non-invasively with diffusion NMR. We present a method to quantify the intracellular lifetime of water in cell suspensions with short transverse relaxation times, T2, and also circumvent the confounding effect of different T2 values in the intra- and extracellular compartments. Filter exchange spectroscopy (FEXSY) is specifically sensitive to exchange between compartments with different apparent diffusivities. Our investigation shows that FEXSY could yield significantly biased results if differences in T2 are not accounted for. To mitigate this problem, we propose combining FEXSY with diffusion-relaxation correlation experiment, which can quantify differences in T2 values in compartments with different diffusivities. Our analysis uses a joint constrained fitting of the two datasets and considers the effects of diffusion, relaxation and exchange in both experiments. The method is demonstrated on yeast cells with and without human aquaporins.
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| 9. |
- Hedlund, Gunnar, et al.
(författare)
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The Tumor Targeted Superantigen ABR-217620 Selectively Engages TRBV7-9 and Exploits TCR-pMHC Affinity Mimicry in Mediating T Cell Cytotoxicity.
- 2013
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- The T lymphocytes are the most important effector cells in immunotherapy of cancer. The conceptual objective for developing the tumor targeted superantigen (TTS) ABR-217620 (naptumomab estafenatox, 5T4Fab-SEA/E-120), now in phase 3 studies for advanced renal cell cancer, was to selectively coat tumor cells with cytotoxic T lymphocytes (CTL) target structures functionally similar to natural CTL pMHC target molecules. Here we present data showing that the molecular basis for the anti-tumor activity by ABR-217620 resides in the distinct interaction between the T cell receptor β variable (TRBV) 7-9 and the engineered superantigen (Sag) SEA/E-120 in the fusion protein bound to the 5T4 antigen on tumor cells. Multimeric but not monomeric ABR-217620 selectively stains TRBV7-9 expressing T lymphocytes from human peripheral blood similar to antigen specific staining of T cells with pMHC tetramers. SEA/E-120 selectively activates TRBV7-9 expressing T lymphocytes resulting in expansion of the subset. ABR-217620 selectively triggers TRBV7-9 expressing cytotoxic T lymphocytes to kill 5T4 positive tumor cells. Furthermore, ABR-217620 activates TRBV7-9 expressing T cell line cells in the presence of cell- and bead-bound 5T4 tumor antigen. Surface plasmon resonance analysis revealed that ABR-217620 binds to 5T4 with high affinity, to TRBV7-9 with low affinity and to MHC class II with very low affinity. The T lymphocyte engagement by ABR-217620 is constituted by displaying high affinity binding to the tumor cells (KD approximately 1 nM) and with the mimicry of natural productive immune TCR-pMHC contact using affinities of around 1 µM. This difference in kinetics between the two components of the ABR-217620 fusion protein will bias the binding towards the 5T4 target antigen, efficiently activating T-cells via SEA/E-120 only when presented by the tumor cells.
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| 10. |
- Hofvander, Jakob, et al.
(författare)
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Frequent low-level mutations of protein kinase D2 in angiolipoma
- 2017
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Ingår i: Journal of Pathology. - : WILEY. - 0022-3417 .- 1096-9896. ; 241:5, s. 578-582
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Tidskriftsartikel (refereegranskat)abstract
- Tumours displaying differentiation towards normal fat constitute the most common subgroup of soft tissue neoplasms. A series of such tumours was investigated by whole-exome sequencing followed by targeted ultra-deep sequencing. Eighty per cent of angiolipomas, but not any other tumour type, displayed mutations in the protein kinase D2 (PRKD2) gene, typically in the part encoding the catalytic domain. The absence of other aberrations at the chromosome or RNA level suggests that PRKD2 mutations are critical for angiolipoma development. Consistently, the mutated PRKD2 alleles were present at low (3-15%) frequencies, indicating that only a subset of the tumour cells is affected. Indeed, by sequencing mature fat cells and other cells separately, the former typically showed the highest mutation frequencies. Thus, we hypothesize that altered PRKD2 signalling in the adipocytic cells drives tumourigenesis and, in agreement with its pivotal role in angiogenesis, induces the vessel formation that is characteristic for angiolipoma. Copyright (c) 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley amp; Sons, Ltd.
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