| 1. |
- Abelsson, J, et al.
(författare)
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The outcome of allo-HSCT for 92 patients with myelofibrosis in the Nordic countries.
- 2012
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Ingår i: Bone Marrow Transplantation. - : Nature Publishing Group. - 0268-3369 .- 1476-5365. ; 47:3, s. 380-386
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Tidskriftsartikel (refereegranskat)abstract
- Between 1982 and 2009 a total of 92 patients with myelofibrosis (MF) in chronic phase underwent allo-SCT in nine Nordic transplant centers. Myeloablative conditioning (MAC) was given to 40 patients, and reduced intensity conditioning (RIC) was used in 52 patients. The mean age in the two groups at transplantation was 46±12 and 55±8 years, respectively (P<0.001). When adjustment for age differences was made, the survival of the patients treated with RIC was significantly better (P=0.003). Among the RIC patients, the survival was significantly (P=0.003) better for the patients with age <60 years (a 10-year survival close to 80%) than for the older patients. The type of stem cell donor did not significantly affect the survival. No significant difference was found in TRM at 100 days between the MAC- and the RIC-treated patients. The probability of survival at 5 years was 49% for the MAC-treated patients and 59% in the RIC group (P=0.125). Patients treated with RIC experienced significantly less aGVHD compared with patients treated with MAC (P<0.001). The OS at 5 years was 70, 59 and 41% for patients with Lille score 0, 1 and 2, respectively (P=0.038, when age adjustment was made). Twenty-one percent of the patients in the RIC group were given donor lymphocyte infusion because of incomplete donor chimerism, compared with none of the MAC-treated patients (P<0.002). Nine percent of the patients needed a second transplant because of graft failure, progressive disease or transformation to AML, with no significant difference between the groups. Our conclusions are (1) allo-SCT performed with RIC gives a better survival compared with MAC. (2) age over 60 years is strongly related to a worse outcome and (3) patients with higher Lille score had a shorter survival.
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| 2. |
- Abildgaard, Amanda B., et al.
(författare)
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HSP70-binding motifs function as protein quality control degrons
- 2023
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Ingår i: Cellular and Molecular Life Sciences (CMLS). - : Springer Science and Business Media LLC. - 1420-682X .- 1420-9071. ; 80:1
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Tidskriftsartikel (refereegranskat)abstract
- Protein quality control (PQC) degrons are short protein segments that target misfolded proteins for proteasomal degradation, and thus protect cells against the accumulation of potentially toxic non-native proteins. Studies have shown that PQC degrons are hydrophobic and rarely contain negatively charged residues, features which are shared with chaperone-binding regions. Here we explore the notion that chaperone-binding regions may function as PQC degrons. When directly tested, we found that a canonical Hsp70-binding motif (the APPY peptide) functioned as a dose-dependent PQC degron both in yeast and in human cells. In yeast, Hsp70, Hsp110, Fes1, and the E3 Ubr1 target the APPY degron. Screening revealed that the sequence space within the chaperone-binding region of APPY that is compatible with degron function is vast. We find that the number of exposed Hsp70-binding sites in the yeast proteome correlates with a reduced protein abundance and half-life. Our results suggest that when protein folding fails, chaperone-binding sites may operate as PQC degrons, and that the sequence properties leading to PQC-linked degradation therefore overlap with those of chaperone binding.
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| 3. |
- Agardh, Emilie E., et al.
(författare)
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Alcohol and type 2 diabetes : The role of socioeconomic, lifestyle and psychosocial factors
- 2019
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Ingår i: Scandinavian Journal of Public Health. - : SAGE Publications. - 1403-4948 .- 1651-1905. ; 47:4, s. 408-416
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: We investigate (a) alcohol consumption in association with type 2 diabetes, taking heavy episodic drinking (HED), socioeconomic, health and lifestyle, and psychosocial factors into account, and (b) whether a seemingly protective effect of moderate alcohol consumption on type 2 diabetes persists when stratified by occupational position.METHODS: This population-based longitudinal cohort study comprises 16,223 Swedes aged 18-84 years who answered questionnaires about lifestyle, including alcohol consumption in 2002, and who were followed-up for self-reported or register-based diabetes in 2003-2011. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated in a multivariable-adjusted logistic regression model for all participants and stratified by high and low occupational position. We adjusted for HED, socioeconomic (occupational position, cohabiting status and unemployment), health and lifestyle (body mass index (BMI), blood pressure, smoking, physical inactivity, poor general health, anxiety/depression and psychosocial (low job control and poor social support) characteristics one by one, and the sets of these factors.RESULTS: Moderate consumption was inversely associated with type 2 diabetes after controlling for health and lifestyle (OR=0.47; 95% CI: 0.29-0.79) and psychosocial factors (OR=0.40; 95% CI: 0.22-0.79) when compared to non-drinkers. When adjusting for socioeconomic factors, there was still an inverse but non-significant association (OR=0.59; 95% CI: 0.35-1.00). In those with high occupational position, there was no significant association between moderate consumption and type 2 diabetes after adjusting for socioeconomic (OR=0.67; 95% CI: 0.3-1.52), health and lifestyle (OR=0.70; 95% CI: 0.32-1.5), and psychosocial factors (OR=0.75; 95% CI: 0.23-2.46). On the contrary, in those with low occupational position, ORs decreased from 0.55 (95% CI: 0.28-1.1) to 0.35 (95% CI: 0.15-0.82) when adjusting for psychosocial factors, a decrease that was solely due to low job control. HED did not influence any of these associations.CONCLUSIONS: Moderate alcohol consumption is associated with a lower risk of type 2 diabetes, after adjusting for HED, health and lifestyle, and psychosocial characteristics. The association was inverse but non-significant after adjusting for socioeconomic factors. When stratified by occupational position, there was an inverse association only in those with low occupational position and after adjusting for low job control.
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| 4. |
- Álvarez-Guerra, Irene, 1995-, et al.
(författare)
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LDO proteins and Vac8 form a vacuole-lipid droplet contact site to enable starvation-induced lipophagy in yeast
- 2024
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Ingår i: Developmental Cell. - 1534-5807 .- 1878-1551. ; 59:6, s. 759-775, e1-e5
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Tidskriftsartikel (refereegranskat)abstract
- Lipid droplets (LDs) are fat storage organelles critical for energy and lipid metabolism. Upon nutrient exhaustion, cells consume LDs via gradual lipolysis or via lipophagy, the en bloc uptake of LDs into the vacuole. Here, we show that LDs dock to the vacuolar membrane via a contact site that is required for lipophagy in yeast. The LD-localized LDO proteins carry an intrinsically disordered region that directly binds vacuolar Vac8 to form vCLIP, the vacuolar-LD contact site. Nutrient limitation drives vCLIP formation, and its inactivation blocks lipophagy, resulting in impaired caloric restriction-induced longevity. We establish a functional link between lipophagy and microautophagy of the nucleus, both requiring Vac8 to form respective contact sites upon metabolic stress. In sum, we identify the tethering machinery of vCLIP and find that Vac8 provides a platform for multiple and competing contact sites associated with autophagy.
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| 5. |
- Andreasson, Claes, et al.
(författare)
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Direct Cloning of Isogenic Murine DNA in Yeast and Relevance of Isogenicity for Targeting in Embryonic Stem Cells
- 2013
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 8:9, s. e74207-
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Tidskriftsartikel (refereegranskat)abstract
- Efficient gene targeting in embryonic stem cells requires that modifying DNA sequences are identical to those in the targeted chromosomal locus. Yet, there is a paucity of isogenic genomic clones for human cell lines and PCR amplification cannot be used in many mutation-sensitive applications. Here, we describe a novel method for the direct cloning of genomic DNA into a targeting vector, pRTVIR, using oligonucleotide-directed homologous recombination in yeast. We demonstrate the applicability of the method by constructing functional targeting vectors for mammalian genes Uhrf1 and Gfap. Whereas the isogenic targeting of the gene Uhrf1 showed a substantial increase in targeting efficiency compared to non-isogenic DNA in mouse E14 cells, E14-derived DNA performed better than the isogenic DNA in JM8 cells for both Uhrf1 and Gfap. Analysis of 70 C57BL/6-derived targeting vectors electroporated in JM8 and E14 cell lines in parallel showed a clear dependence on isogenicity for targeting, but for three genes isogenic DNA was found to be inhibitory. In summary, this study provides a straightforward methodological approach for the direct generation of isogenic gene targeting vectors.
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| 6. |
- Andréasson, Claes
(författare)
-
Ligand-activated proteolysis in nutrient signaling
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cells respond to changing nutrient availability and make adjustments in physiological processes. Central for making proper adjustments is the ability to execute appropriate changes in patterns of gene expression. The budding yeast Saccharomyces cerevisiae, responds to the presence of extracellular amino acids by up regulating systems that internalize these nutrients. Extracellular amino acids are sensed by the amino acid transporter-like receptor Ssy1p that is localized to the plasma membrane. Ssy1p generates a signal that is transmitted via a pathway minimally composed of the core components Ssy1p, Ptr3p, and Ssy5p (SPS). The SPS sensor pathway ultimately up regulates genes encoding amino acid transporters, also known as amino acid permeases. This thesis describes the elucidation of the mechanism connecting amino acid induced signals generated at the plasma membrane and gene regulation in the nucleus. A genetic selection for mutations that enable amino acid permease genes to be expressed even in the absence of a functional SPS sensor pathway identified the dominant ASI13-1 mutation. The ASI13-1 gene encodes a constitutively active form of the transcription factor Stp1p that lacks its regulatory N-terminal domain. Stp1p and its close homologue Stp2p are synthesized as latent cytoplasmic precursors. In response to extracellular amino acids, the SPS sensor induces the rapid endoproteolytic processing of Stp1p and Stp2p. The shorter forms of these transcription factors, lacking N-terminal inhibitory domains, are targeted to the nucleus, where they transactivate SPS-sensor target genes. Several genetic approaches have been applied to identify mutations that affect the SPS sensor pathway. A novel genetic selection specifically designed for rare mutations that affect the SPS-sensing pathway identified the F-box protein Grr1p as an obligatory factor required for Stp1p and Stp2p processing. Genetic analysis suggests that Grr1p has a role in signal transduction within the SPS sensor. The N-terminal domains of Stp1p and Stp2p contain two conserved motifs that are required for proper nuclear exclusion and proteolytic processing. These motifs function in parallel; mutations that abolish processing inhibit signaling, whereas mutations that interfere with cytoplasmic retention result in constitutive activation of SPS sensorregulated genes independently of processing. The N-terminal domain of Stp1p is functionally autonomous and transferable to other transcription factors, where its presence confers regulated nuclear exclusion and SPS sensor-induced proteolytic processing. Proteolytic processing of recombinant Stp1p in cell free lysates supports the notion of a SPS sensor activated protease. Analysis indicates that Ssy5p is a chymotrypsin-like serine protease that is activated via the SPS sensor pathway and is responsible for Stp1p and Stp2p processing. Mutations in the predicted catalytic triad of Ssy5p abolish Stp1p processing. A constitutive SSY5 mutant promotes processing of Stp1p even in the absence of amino acids or Ssy1p and Ptr3p. Finally, Stp1p is processed when heterologously coexpressed together with activated Ssy5p in Schizosaccharomyces pombe, an organism that lacks the SPS sensor pathway. Taken together, these results define a unique and streamline metabolic control pathway that directly routes nutrient signals initiated at the plasma membrane to transcriptional activation in the nucleus.
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| 7. |
- Andréasson, Claes, et al.
(författare)
-
Mitochondria orchestrate proteostatic and metabolic stress responses
- 2019
-
Ingår i: EMBO Reports. - : EMBO. - 1469-221X .- 1469-3178. ; 20:10
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Tidskriftsartikel (refereegranskat)abstract
- The eukaryotic cell is morphologically and functionally organized as an interconnected network of organelles that responds to stress and aging. Organelles communicate via dedicated signal transduction pathways and the transfer of information in form of metabolites and energy levels. Recent data suggest that the communication between organellar proteostasis systems is a cornerstone of cellular stress responses in eukaryotic cells. Here, we discuss the integration of proteostasis and energy fluxes in the regulation of cellular stress and aging. We emphasize the molecular architecture of the regulatory transcriptional pathways that both sense and control metabolism and proteostasis. A special focus is placed on mechanistic insights gained from the model organism budding yeast in signaling from mitochondria to the nucleus and how this shapes cellular fitness.
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| 8. |
- Andréasson, Claes, et al.
(författare)
-
The endoplasmic reticulum Grp170 acts as a nucleotide exchange factor of Hsp70 via a mechanism similar to that of the cytosolic Hsp11
- 2010
-
Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 285:16, s. 12445-53
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Tidskriftsartikel (refereegranskat)abstract
- Grp170 and Hsp110 proteins constitute two evolutionary distinct branches of the Hsp70 family that share the ability to function as nucleotide exchange factors (NEFs) for canonical Hsp70s. Although the NEF mechanism of the cytoplasmic Hsp110s is well understood, little is known regarding the mechanism used by Grp170s in the endoplasmic reticulum. In this study, we compare the yeast Grp170 Lhs1 with the yeast Hsp110 Sse1. We find that residues important for Sse1 NEF activity are conserved in Lhs1 and that mutations in these residues in Lhs1 compromise NEF activity. As previously reported for Sse1, Lhs1 requires ATP to trigger nucleotide exchange in its cognate Hsp70 partner Kar2. Using site-specific cross-linking, we show that the nucleotide-binding domain (NBD) of Lhs1 interacts with the NBD of Kar2 face to face, and that Lhs1 contacts the side of the Kar2 NBD via its protruding C-terminal alpha-helical domain. To directly address the mechanism of nucleotide exchange, we have compared the hydrogen-exchange characteristics of a yeast Hsp70 NBD (Ssa1) in complex with either Sse1 or Lhs1. We find that Lhs1 and Sse1 induce very similar changes in the conformational dynamics in the Hsp70. Thus, our findings demonstrate that despite some differences between Hsp110 and Grp170 proteins, they use a similar mechanism to trigger nucleotide exchange.
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| 9. |
- Andreasson, Jens, 1978, et al.
(författare)
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”Den missförstådda traditionsprincipen”
- 2020
-
Ingår i: Dagens Juridik. ; :2020-10-06
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- I dagarna har en av landets största dagstidningar på sin ledarsida krävt traditionsprincipens avskaffande. Ledaraspekten av krönikan kan sammanfattas i att det är olyckligt att okända juridiska principer påverkar vår tillvaro och vår exportindustri! Den åsikten påminner om åsikterna bakom lagförslaget SOU 2015:18 Lösöreköp och registerpant.
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| 10. |
- Andreasson, Jens, 1978, et al.
(författare)
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Efficient priority rules under default: the case of traditio versus contract principle
- 2021
-
Ingår i: European Journal of Law and Economics. - : Springer Science and Business Media LLC. - 0929-1261 .- 1572-9990. ; 51:1, s. 97-128
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the economic consequences of the traditio and the contract principle-differing in how they determine the priority rights for an item sold but not delivered. Our results suggest that the two principles are equivalent in terms of the net utilities enjoyed by involved actors. For example, a lower price paid for a forward transaction under a traditio principle can be compensated by better credit terms, implying there is no competitive advantage for either the seller or buyer under any principle. We demonstrate how market prices, incorrectly used, may misleadingly favour a contract principle, and discuss how fraudulent behaviour better supports a traditio regime. We also contribute to the legal discussion on priority regimes of undelivered items basing our discussion on bankruptcy priority laws instead of distribution of ownership.
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| 11. |
- Andreasson, Jens, 1978, et al.
(författare)
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Prioritet för köpare - en fråga om tradition eller princip?
- 2015
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Ingår i: Svensk Juristtidning. - 0039-6591. ; :9, s. 709-748
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Lösöreköpskommittén har i SOU 2015:18 föreslagit bl.a. att traditionsprincipen bör avskaffas. I denna artikel presenteras några resultat av en enkel argumentationsanalys avseende kommitténs argumentation. Analysen indikerar att kommittén haft en normativ ambition snarare än en utredande. Resultaten är därför relevanta för dem som är intresserade av den reella frågan om prioritet för köpare. Möjligen är artikeln också relevant som ett generellt exempel på en kritisk analys av argumentationen i en offentlig utredning.
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| 12. |
- Andreasson, Jens, 1978, et al.
(författare)
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Some Problems in the Relationship Between Economics and Law
- 2017
-
Ingår i: in Lensink, R., Sjögren, S. & Wihlborg, C. (Eds.) (2017). Paths for Sustainable Economic Development A Festschrift for Shubhashis Gangopadhyay on his 60th birthday.. - : University of Gothenburg, Chapman University, University of Groningen. - 9789163952159 ; , s. 353-362
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 13. |
- Andréasson, Sara Näslund, et al.
(författare)
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Peritonectomy with high voltage electrocautery generates higher levels of ultrafine smoke particles
- 2008
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Ingår i: European Journal of Surgical Oncology. - : Elsevier BV. - 0748-7983 .- 1532-2157. ; 35:7, s. 780-784
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: To adequately perform peritonectomy, the use of an electrocautery device at a high voltage is recommended. The aim of this study was to analyse the amount of airborne and ultrafine particles (UFP) generated during peritonectomy and to compare this with standard colon and rectal cancer surgery (CRC). METHOD: UFP was measured approximately 2-3cm from the breathing area of the surgeon (personal sampling) and 3m from where the electrocautery smoke was generated (stationary sampling) from 14 consecutive peritonectomy procedures and 11 standard CRC resections. The sampling was by P-Trak UFP counter that has the capacity to detect particle size ranging from 0.02 to 1mum. RESULTS: The cumulative level of UFP of personal sampling in the peritonectomy group was higher (9.3x10(6)particle/ml/h (pt/ml/h)) than in the control group (4.8x10(5)pt/ml/h). A higher cumulative level of UFP in stationary sampling was observed in the PC group (2.6x10(6) pt/ml/h) than in the control group (3.9x10(4)pt/ml/h). CONCLUSION: Peritonectomy procedure with high voltage electrocautery generates elevated levels of UFP than standard CRC surgery does. The level of UFP produced by a peritonectomy is comparable to cigarette smoking. More efficient smoke evacuator systems are needed in order to reduce the levels of UFP generated during electrocautery surgery.
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| 14. |
- Bjorkholm, M., et al.
(författare)
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Treatment-related risk factors for transformation to acute myeloid leukemia and myelodysplastic syndromes in myeloproliferative neoplasms
- 2011
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Ingår i: Journal of Clinical Oncology. - : American Society of Clinical Oncology: JCO. - 0732-183X .- 1527-7755. ; 29:17, s. 2410-2415
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Patients with myeloproliferative neoplasms (MPNs), including polycythemia vera, essential thrombocythemia, and primary myelofibrosis, have a propensity to develop acute myeloid leukemia (AML) and myelodysplastic syndromes (MDSs). Using population-based data from Sweden, we assessed the role of MPN treatment and subsequent AML/MDS risk with special focus on the leukemogenic potential of hydroxyurea (HU). Methods: On the basis of a nationwide MPN cohort (N = 11,039), we conducted a nested case-control study, including 162 patients (153 and nine with subsequent AML and MDS diagnosis, respectively) and 242 matched controls. We obtained clinical and MPN treatment data for all patients. Using logistic regression, we calculated odds ratios (ORs) as measures of AML/MDS risk. Results: Forty-one (25%) of 162 patients with MPNs with AML/MDS development were never exposed to alkylating agents, radioactive phosphorous (P32), or HU. Compared with patients with who were not exposed to HU, the ORs for 1 to 499 g, 500 to 999 g, more than 1,000 g of HU were 1.5 (95% CI, 0.6 to 2.4), 1.4 (95% CI, 0.6 to 3.4), and 1.3 (95% CI, 0.5 to 3.3), respectively, for AML/MDS development (not significant). Patients with MPNs who received P32 greater than 1,000 MBq and alkylators greater than 1 g had a 4.6-fold (95% CI, 2.1 to 9.8; P = .002) and 3.4-fold (95% CI, 1.1 to 10.6; P = .015) increased risk of AML/MDS, respectively. Patients receiving two or more cytoreductive treatments had a 2.9-fold (95% CI, 1.4 to 5.9) increased risk of transformation. Conclusion: The risk of AML/MDS development after MPN diagnosis was significantly associated with high exposures of P32 and alkylators but not with HU treatment. Twenty-five percent of patients with MPNs who developed AML/MDS were not exposed to cytotoxic therapy, supporting a major role for nontreatment-related factors. © 2011 by American Society of Clinical Oncology.
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| 15. |
- Ciccarelli, Michela, et al.
(författare)
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Genetic inactivation of essential HSF1 reveals an isolated transcriptional stress response selectively induced by protein misfolding
- 2023
-
Ingår i: Molecular Biology of the Cell. - 1059-1524 .- 1939-4586. ; 34:11
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Tidskriftsartikel (refereegranskat)abstract
- Heat Shock Factor 1 (Hsf1) in yeast drives the basal transcription of key proteostasis factors and its activity is induced as part of the core heat shock response. Exploring Hsf1 specific functions has been challenging due to the essential nature of the HSF1 gene and the extensive overlap of target promoters with environmental stress response (ESR) transcription factors Msn2 and Msn4 (Msn2/4). In this study, we constructed a viable hsf1 increment strain by replacing the HSF1 open reading frame with genes that constitutively express Hsp40, Hsp70, and Hsp90 from Hsf1-independent promoters. Phenotypic analysis showed that the hsf1 increment strain grows slowly, is sensitive to heat as well as protein misfolding and accumulates protein aggregates. Transcriptome analysis revealed that the transcriptional response to protein misfolding induced by azetidine-2-carboxylic acid is fully dependent on Hsf1. In contrast, the hsf1 increment strain responded to heat shock through the ESR. Following HS, Hsf1 and Msn2/4 showed functional compensatory induction with stronger activation of the remaining stress pathway when the other branch was inactivated. Thus, we provide a long-overdue genetic test of the function of Hsf1 in yeast using the novel hsf1 increment construct. Our data highlight that the accumulation of misfolded proteins is uniquely sensed by Hsf1-Hsp70 chaperone titration inducing a highly selective transcriptional stress response.
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| 16. |
- Forsman, Huamei, et al.
(författare)
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Reactivation of Desensitized Formyl Peptide Receptors by Platelet Activating Factor: A Novel Receptor Cross Talk Mechanism Regulating Neutrophil Superoxide Anion Production
- 2013
-
Ingår i: Plos One. - : Public Library of Science (PLoS). - 1932-6203. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- Neutrophils express different chemoattractant receptors of importance for guiding the cells from the blood stream to sites of inflammation. These receptors communicate with one another, a cross talk manifested as hierarchical, heterologous receptor desensitization. We describe a new receptor cross talk mechanism, by which desensitized formyl peptide receptors (FPRdes) can be reactivated. FPR desensitization is induced through binding of specific FPR agonists and is reached after a short period of active signaling. The mechanism that transfers the receptor to a non-signaling desensitized state is not known, and a signaling pathway has so far not been described, that transfers FPRdes back to an active signaling state. The reactivation signal was generated by PAF stimulation of its receptor (PAFR) and the cross talk was uni-directional. LatrunculinA, an inhibitor of actin polymerization, induced a similar reactivation of FPRdes as PAF while the phosphatase inhibitor CalyculinA inhibited reactivation, suggesting a role for the actin cytoskeleton in receptor desensitization and reactivation. The activated PAFR could, however, reactivate FPRdes also when the cytoskeleton was disrupted prior to activation. The receptor cross talk model presented prophesies that the contact on the inner leaflet of the plasma membrane that blocks signaling between the G-protein and the FPR is not a point of no return; the receptor cross-talk from the PAFRs to the FPRdes initiates an actin-independent signaling pathway that turns desensitized receptors back to a signaling state. This represents a novel mechanism for amplification of neutrophil production of reactive oxygen species.
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| 17. |
- Forsman, Huamei, et al.
(författare)
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Structural Characterization and Inhibitory Profile of Formyl Peptide Receptor 2 Selective Peptides Descending from a PIP2-Binding Domain of Gelsolin.
- 2012
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 189:2, s. 629-637
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Tidskriftsartikel (refereegranskat)abstract
- The neutrophil formyl peptide receptors, FPR1 and FPR2, play critical roles for inflammatory reactions, and receptor-specific antagonists/inhibitors can possibly be used to facilitate the resolution of pathological inflammatory reactions. A 10-aa-long rhodamine-linked and membrane-permeable peptide inhibitor (PBP10) has such a potential. This FPR2 selective inhibitor adopts a phosphatidylinositol 4,5-bisphosphate-binding sequence in the cytoskeletal protein gelsolin. A core peptide, RhB-QRLFQV, is identified that displays inhibitory effects as potent as the full-length molecule. The phosphatidylinositol 4,5-bisphosphate-binding capacity of PBP10 was not in its own sufficient for inhibition. A receptor in which the presumed cytoplasmic signaling C-terminal tail of FPR2 was replaced with that of FPR1 retained the PBP10 sensitivity, suggesting that the tail of FPR2 was not on its own critical for inhibition. This gains support from the fact that the effect of cell-penetrating lipopeptide (a pepducin), suggested to act primarily through the third intracellular loop of FPR2, was significantly inhibited by PBP10. The third intracellular loops of FPR1 and FPR2 differ in only two amino acids, but an FPR2 mutant in which these two amino acids were replaced by those present in FPR1 retained the PBP10 sensitivity. In summary, we conclude that the inhibitory activity on neutrophil function of PBP10 is preserved in the core sequence RhB-QRLFQV and that neither the third intracellular loop of FPR2 nor the cytoplasmic tail of the receptor alone is responsible for the specific inhibition.
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| 18. |
- Forsman, Huamei, et al.
(författare)
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WHAT FORMYL PEPTIDE RECEPTORS, IF ANY, ARE TRIGGERED BY COMPOUND 43 AND LIPOXIN A(4) ?
- 2011
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Ingår i: Scandinavian journal of immunology. - : Wiley. - 1365-3083 .- 0300-9475.
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Tidskriftsartikel (refereegranskat)abstract
- In this study we determined receptor preferences for compound 43, a nitrosylated pyrazolone derivative, and the eicosanoid lipoxin A(4) (LXA(4) ), potent anti-inflammatory mediators in many experimental in vivo models Their effects have been suggested to be mediated through binding to FPR2 (earlier known as FPRL1 or ALXR), one of the two members of the formyl peptide receptor family expressed in neutrophils. Compound 43 activates all neutrophil functions investigated whereas LXA(4) induces a unique inhibiting pathway suggested to involve β-arrestin binding as an early signaling step, but not a transient rise in intracellular Ca(2+) . We show that compound 43 can activate not only FPR2 but also FPR1 the other neutrophil receptor in the FPR family, and FPR1 is actually the preferred receptor in human neutrophils and possibly also in the murine equivalent. LXA(4) analogues from two commercial sources were used, and neither of these induced any translocation of β-arrestin as measured in an enzyme-fragment-complementation assay. The conclusions drawn from these experiments are that neither compound 43 nor LXA(4) work as FPR2 agonists in neutrophils, findings of importance for a proper interpretation of results obtained with these compounds as regulators of inflammation.
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| 19. |
- Fritzell, Kajsa, et al.
(författare)
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Sensitive ADAR editing reporter in cancer cells enables high-throughput screening of small molecule libraries
- 2019
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 47:4
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Tidskriftsartikel (refereegranskat)abstract
- Adenosine to inosine editing is common in the human transcriptome and changes of this essential activity is associated with disease. Children with ADAR1 mutations develop fatal Aicardi-Goutieres syndrome characterized by aberrant interferon expression. In contrast, ADAR1 overexpression is associated with increased malignancy of breast, lung and liver cancer. ADAR1 silencing in breast cancer cells leads to increased apoptosis, suggesting an anti-apoptotic function that promotes cancer progression. Yet, suitable high-throughput editing assays are needed to efficiently screen chemical libraries for modifiers of ADAR1 activity. We describe the development of a bioluminescent reporter system that facilitates rapid and accurate determination of endogenous editing activity. The system is based on the highly sensitive and quantitative Nanoluciferase that is conditionally expressed upon reporter-transcript editing. Stably introduced into cancer cell lines, the system reports on elevated endogenous ADAR1 editing activity induced by interferon as well as knockdown of ADAR1 and ADAR2. In a single-well setup we used the reporter in HeLa cells to screen a small molecule library of 33 000 compounds. This yielded a primary hit rate of 0.9% at 70% inhibition of editing. Thus, we provide a key tool for high-throughput identification of modifiers of A-to-I editing activity in cancer cells.
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| 20. |
- Gersing, Sarah K., et al.
(författare)
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Mapping the degradation pathway of a disease-linked aspartoacylase variant
- 2021
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 17:4
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Tidskriftsartikel (refereegranskat)abstract
- Canavan disease is a severe progressive neurodegenerative disorder that is characterized by swelling and spongy degeneration of brain white matter. The disease is genetically linked to polymorphisms in the aspartoacylase (ASPA) gene, including the substitution C152W. ASPA C152W is associated with greatly reduced protein levels in cells, yet biophysical experiments suggest a wild-type like thermal stability. Here, we use ASPA C152W as a model to investigate the degradation pathway of a disease-causing protein variant. When we expressed ASPA C152W in Saccharomyces cerevisiae, we found a decreased steady state compared to wild-type ASPA as a result of increased proteasomal degradation. However, molecular dynamics simulations of ASPA C152W did not substantially deviate from wild-type ASPA, indicating that the native state is structurally preserved. Instead, we suggest that the C152W substitution interferes with the de novo folding pathway resulting in increased proteasomal degradation before reaching its stable conformation. Systematic mapping of the protein quality control components acting on misfolded and aggregation-prone species of C152W, revealed that the degradation is highly dependent on the molecular chaperone Hsp70, its co-chaperone Hsp110 as well as several quality control E3 ubiquitin-protein ligases, including Ubr1. In addition, the disaggregase Hsp104 facilitated refolding of aggregated ASPA C152W, while Cdc48 mediated degradation of insoluble ASPA protein. In human cells, ASPA C152W displayed increased proteasomal turnover that was similarly dependent on Hsp70 and Hsp110. Our findings underscore the use of yeast to determine the protein quality control components involved in the degradation of human pathogenic variants in order to identify potential therapeutic targets. Author summary Canavan disease is a fatal neurodegenerative disorder which is genetically linked to polymorphisms in the aspartoacylase (ASPA) gene. Although the molecular mechanism of most disease-causing substitutions remains to be examined, some variants have been suggested to cause the loss-of-function phenotype by perturbing the structural stability of ASPA. So far the cellular fate of these variants have not been examined. Here we examine the stability and degradation pathways of the disease-causing ASPA variant C152W. In yeast cells, ASPA C152W showed decreased steady-state protein levels as a result of increased proteasomal turnover. Our molecular dynamics simulations showed that the C152W substitution did not globally perturb the native structure of ASPA. Instead we propose that ASPA C152W is targeted by the protein quality control system during de novo folding. Specifically, we found that the molecular chaperone Hsp70, its co-chaperone Hsp110, and the E3 ubiquitin-protein ligase Ubr1 promote degradation of ASPA C152W. When we expressed ASPA C152W in cultured human cells, we found that Hsp70 and Hsp110 similarly mediated degradation. Therefore, we propose that Hsp110 should be further examined as a potential therapeutic target in Canavan disease and other protein misfolding diseases.
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| 21. |
- Gestin, Maxime, 1990-, et al.
(författare)
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Transfection of Heat Shock Protein 70 kDa (HSP70)
- 2022
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Ingår i: International Journal of Peptide Research and Therapeutics. - : Springer Science and Business Media LLC. - 1573-3904 .- 1573-3149. ; 28:4
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Tidskriftsartikel (refereegranskat)abstract
- Heat shock protein 70 kDa (HSP70) is a major protein family in the cell protections against stress-induced denaturation and aggregation and in the folding of nascent proteins. It is a highly conserved protein that can be found in most organisms and is strongly connected to several intracellular pathways such as protein folding and refolding, protein degradation and regulation, and protection against intense stress. Cellular delivery of HSP70 would be of high impact for clarification of its role in these cellular processes.PepFect14 is a cell-penetrating peptide known to be able to mediate the transfection of various oligonucleotides to multiple cell lines with a higher efficacy than most commercially available transfection agents and without inducing significant toxic effects.In this study we demonstrated that PepFect14 was able to form a complex with HSP70 and to deliver it inside cells in the same fashion with oligonucleotide delivery. The delivered HSP70 showed an effect in the cell regulation indicating that the protein was biologically available in the cytoplasm and the interactions with PepFect14 did not impeach its active sites once the plasma barrier crossed.This study reports the first successful delivery of HSP70 to our knowledge and the first protein transfection mediated by PepFect14. It opens new fields of research for both PepFect14 as a delivery agent and HSP70 as a therapeutic agent; with potential in peptide aggregation caused diseases such as Parkinson’s and Alzheimer’s diseases.
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| 22. |
- Gestin, Maxime, 1990-, et al.
(författare)
-
Transfection of Heat Shock Protein70kDa (HSP70)
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Heat shock protein 70kDa (HSP70) is a major protein family in the cell protections against stress-induced denaturation and aggregation and in the folding of nascent proteins. It is a highly conserved protein that can be found in most organisms and is strongly connected to several intracellular pathways such as protein folding and refolding, protein degradation and regulation, and protection against intense stress. Cellular delivery of HSP70 would be of high impact for clarification of its role in these cellular processes. PepFect14 is a cell-penetrating peptide known to be able to mediate the transfection of various oligonucleotides to multiple cell lines with a higher efficacy than most commercially available transfection agents and without inducing significant toxic effects. In this study we demonstrated that PepFect14 was able to form a complex with HSP70 and to deliver it inside cells in the same fashion with oligonucleotide delivery. The delivered HSP70 showed an effect in the cell regulation indicating that the protein was biologically available in the cytoplasm and the interactions with PepFect14 did not impeach its active sites once the plasma barrier crossed. This study reports the first successful delivery of HSP70 to our knowledge and the first protein transfection mediated by PepFect14. It opens new fields of research for both PepFect14 as a delivery agent and HSP70 as a therapeutic agent; with potential in peptide aggregation caused diseases such as Parkinson’s and Alzheimer’s diseases.
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| 23. |
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| 24. |
- Gowda, Naveen Kumar Chandappa, et al.
(författare)
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Cytosolic splice isoform of Hsp70 nucleotide exchange factor Fes1 is required for the degradation of misfolded proteins in yeast
- 2016
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Ingår i: Molecular Biology of the Cell. - 1059-1524 .- 1939-4586. ; 27:8, s. 1210-1219
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Tidskriftsartikel (refereegranskat)abstract
- Cells maintain proteostasis by selectively recognizing and targeting misfolded proteins for degradation. In Saccharomyces cerevisiae, the Hsp70 nucleotide exchange factor Fes1 is essential for the degradation of chaperone-associated misfolded proteins by the ubiquitin-proteasome system. Here we show that the FES1 transcript undergoes unique 3' alternative splicing that results in two equally active isoforms with alternative C-termini, Fes1L and Fes1S. Fes1L is actively targeted to the nucleus and represents the first identified nuclear Hsp70 nucleotide exchange factor. In contrast, Fes1S localizes to the cytosol and is essential to maintain proteostasis. In the absence of Fes1S, the heat-shock response is constitutively induced at normally non-stressful conditions. Moreover, cells display severe growth defects when elevated temperatures, amino acid analogues or the ectopic expression of misfolded proteins, induce protein misfolding. Importantly, misfolded proteins are not targeted for degradation by the ubiquitin-proteasome system. These observations support the notion that cytosolic Fes1S maintains proteostasis by supporting the removal of toxic misfolded proteins by proteasomal degradation. This study provides key findings for the understanding of the organization of protein quality control mechanisms in the cytosol and nucleus.
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| 25. |
- Gowda, Naveen Kumar Chandappa, et al.
(författare)
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Hsp70 nucleotide exchange factor Fes1 is essential for ubiquitin-dependent degradation of misfolded cytosolic proteins
- 2013
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 110:15, s. 5975-5980
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Tidskriftsartikel (refereegranskat)abstract
- Protein quality control systems protect cells against the accumulation of toxic misfolded proteins by promoting their selective degradation. Malfunctions of quality control systems are linked to aging and neurodegenerative disease. Folding of polypeptides is facilitated by the association of 70 kDa Heat shock protein (Hsp70) molecular chaperones. If folding cannot be achieved, Hsp70 interacts with ubiquitylation enzymes that promote the proteasomal degradation of the misfolded protein. However, the factors that direct Hsp70 substrates toward the degradation machinery have remained unknown. Here, we identify Fes1, an Hsp70 nucleotide exchange factor of hitherto unclear physiological function, as a cytosolic triaging factor that promotes proteasomal degradation of misfolded proteins. Fes1 selectively interacts with misfolded proteins bound by Hsp70 and triggers their release from the chaperone. In the absence of Fes1, misfolded proteins fail to undergo polyubiquitylation, aggregate, and induce a strong heat shock response. Our findings reveal that Hsp70 direct proteins toward either folding or degradation by using distinct nucleotide exchange factors.
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| 26. |
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| 27. |
- Gowda, Naveen K. C., et al.
(författare)
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Nucleotide exchange factors Fes1 and HspBP1 mimic substrate to release misfolded proteins from Hsp70
- 2018
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Ingår i: Nature Structural & Molecular Biology. - : Springer Science and Business Media LLC. - 1545-9993 .- 1545-9985. ; 25:1, s. 83-
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Tidskriftsartikel (refereegranskat)abstract
- Protein quality control depends on the tight regulation of interactions between molecular chaperones and polypeptide substrates. Substrate release from the chaperone Hsp70 is triggered by nucleotide-exchange factors (NEFs) that control folding and degradation fates via poorly understood mechanisms. We found that the armadillo-type NEFs budding yeast Fes1 and its human homolog HspBP1 employ flexible N-terminal release domains (RDs) with substrate-mimicking properties to ensure the efficient release of persistent substrates from Hsp70. The RD contacts the substrate-binding domain of the chaperone, competes with peptide substrate for binding and is essential for proper function in yeast and mammalian cells. Thus, the armadillo domain engages Hsp70 to trigger nucleotide exchange, whereas the RD safeguards the release of substrates. Our findings provide fundamental mechanistic insight into the functional specialization of Hsp70 NEFs and have implications for the understanding of proteostasis-related disorders, including Marinesco-Sjögren syndrome.
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| 28. |
- Gowda, Naveen Kumar Chandappa, 1984-
(författare)
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Regulation of Hsp70 function by nucleotide-exchange factors
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Protein folding is the process in which polypeptides in their non-native states attain the unique folds of their native states. Adverse environmental conditions and genetic predisposition challenge the folding process and accelerate the production of proteotoxic misfolded proteins. Misfolded proteins are selectively recognized and removed from the cell by processes of protein quality control (PQC). In PQC molecular chaperones of the Heat shock protein 70 kDa (Hsp70) family play important roles by recognizing and facilitating the removal of misfolded proteins. Hsp70 function is dependent on cofactors that regulate the intrinsic ATPase activity of the chaperone. In this thesis I have used yeast genetic, cell biological and biochemical experiments to gain insight into the regulation of Hsp70 function in PQC by nucleotide-exchange factors (NEFs). Study I shows that the NEF Fes1 is a key factor essential for cytosolic PQC. A reverse genetics approach demonstrated that Fes1 NEF activity is required for the degradation of misfolded proteins associated with Hsp70 by the ubiquitin-proteasome system. Specifically, Fes1 association with Hsp70-substrate complexes promotes interaction of the substrate with downstream ubiquitin E3 ligase Ubr1. The consequences of genetic removal of FES1 (fes1Δ) are the failure to degrade misfolded proteins, the accumulation of protein aggregates and constitutive induction of the heat-shock response. Taken the experimental data together, Fes1 targets misfolded proteins for degradation by releasing them from Hsp70. Study II describes an unusual example of alternative splicing of FES1 transcripts that leads to the expression of the two alternative splice isoforms Fes1S and Fes1L. Both isoforms are functional NEFs but localize to different compartments. Fes1S is localized to the cytosol and is required for the efficient degradation of Hsp70-associated misfolded proteins. In contrast, Fes1L is targeted to the nucleus and represents the first identified nuclear NEF in yeast. The identification of distinctly localized Fes1 isoforms have implications for the understanding of the mechanisms underlying nucleo-cytoplasmic PQC. Study III reports on the mechanism that Fes1 employs to regulate Hsp70 function. Specifically Fes1 carries an N-terminal domain (NTD) that is conserved throughout the fungal kingdom. The NTD is flexible, modular and is required for the cellular function of Fes1. Importantly, the NTD forms ATP-sensitive complexes with Hsp70 suggesting that it competes substrates of the chaperone during Fes1-Hsp70 interactions. Study IV reports on methodological development for the efficient assembly of bacterial protein-expression plasmids using yeast homologous recombination cloning and the novel vector pSUMO-YHRC. The findings support the notion that Fes1 plays a key role in determining the fate of Hsp70-associated misfolded substrates and thereby target them for proteasomal degradation. From a broader perspective, the findings provide information essential to develop models that describe how Hsp70 function is regulated by different NEFs to participate in protein folding and degradation.
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| 29. |
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| 30. |
- Holmberg, Lina, et al.
(författare)
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Trauma triage criteria as predictors of severe injury-a Swedish multicenter cohort study
- 2022
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Ingår i: BMC Emergency Medicine. - : Springer Nature. - 1471-227X. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Adequate performance of trauma team activation (TTA) criteria is important in order to accurately triage trauma patients. The Swedish National Trauma Triage Criteria (SNTTC) consists of 29 criteria that trigger either a Trauma Alert, the highest level of TTA, or a Trauma Response. This study aimed to evaluate the SNTTC and its accuracy in predicting a severely injured patient in a multicenter setting. Methods A cohort study in Sweden involving six trauma receiving hospitals. Data was collected from the Swedish Trauma Registry. Some 626 patients were analyzed with regard to the specific criteria used to initiate the TTA, injury severity with New Injury Severity Score (NISS) and emergency interventions. Sensitivity, specificity, positive predictive value (PPV) and positive likelihood ratio (LR+) of the criteria were calculated, as well as undertriage and overtriage. Results All 29 criteria of SNTTC had a sensitivity > 80% for identifying a severely injured patient. The 16 Trauma Alert Criteria had a lower sensitivity of 62.6% but higher LR+ (3.5 vs all criteria 1.4), specificity (82.3 vs 39.1%) and PPV (55.4 vs 37.6%) and the highest accuracy (AUC 0.724). When using only the six physiological criteria, sensitivity (44.8%) and accuracy (AUC 0.690) decreased while LR+ (6.7), specificity (93.3%) and PPV (70.2%) improved. Conclusion SNTTC is efficient in identifying severely injured patients. The current set of criteria exhibits the best sensitivity compared to other examined combinations and no additional criterion was found to improve the protocol enough to promote a change.
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| 31. |
- Holmberg, Mats A., et al.
(författare)
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A versatile bacterial expression vector designed for single-step cloning of multiple DNA fragments using homologous recombination
- 2014
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Ingår i: Protein Expression and Purification. - : Elsevier BV. - 1046-5928 .- 1096-0279. ; 98, s. 38-45
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Tidskriftsartikel (refereegranskat)abstract
- Production of recombinant proteins is the starting point for biochemical and biophysical analyses and requires methodology to efficiently proceed from gene sequence to purified protein. While optimized strategies for the efficient cloning of single-gene fragments for bacterial expression is available, efficient multiple DNA fragment cloning still presents a challenge. To facilitate this step, we have developed an efficient cloning strategy based on yeast homologous recombination cloning (YHRC) into the new pET-based bacterial expression vector pSUMO-YHRC. The vector supports cloning for untagged expression as well as fusions to His6-SUMO or His6 tags. We demonstrate that YHRC from single PCR products of 6 independent genes into the vector results in virtually no background. Importantly, in a quantitative assay for functional expression we find that single-step YHRC of 7 DNA fragments can be performed with very high cloning efficiencies. The method and reagents described in this paper significantly simplifies the construction of expression plasmids from multiple DNA fragments, including complex gene fusions, chimeric genes and polycistronic constructs.
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| 32. |
- Kaimal, Jayasankar Mohanakrishnan, et al.
(författare)
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Coordinated Hsp110 and Hsp104 Activities Power Protein Disaggregation in Saccharomyces cerevisiae
- 2017
-
Ingår i: Molecular and Cellular Biology. - 0270-7306 .- 1098-5549. ; 37:11
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Tidskriftsartikel (refereegranskat)abstract
- Protein aggregation is intimately associated with cellular stress and is accelerated during aging, disease, and cellular dysfunction. Yeast cells rely on the ATP-consuming chaperone Hsp104 to disaggregate proteins together with Hsp70. Hsp110s are ancient and abundant chaperones that form complexes with Hsp70. Here we provide in vivo data showing that the Saccharomyces cerevisiae Hsp110s Sse1 and Sse2 are essential for Hsp104-dependent protein disaggregation. Following heat shock, complexes of Hsp110 and Hsp70 are recruited to protein aggregates and function together with Hsp104 in the disaggregation process. In the absence of Hsp110, targeting of Hsp70 and Hsp104 to the aggregates is impaired, and the residual Hsp104 that still reaches the aggregates fails to disaggregate. Thus, coordinated activities of both Hsp104 and Hsp110 are required to reactivate aggregated proteins. These findings have important implications for the understanding of how eukaryotic cells manage misfolded and amyloid proteins.
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| 33. |
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| 34. |
- Kaimal, Jayasankar Mohanakrishnan, 1988-
(författare)
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Regulation of cellular Hsp70 : Proteostasis and aggregate management
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Proteins have to be folded to their native structures to be functionally expressed. Misfolded proteins are proteotoxic and negatively impact on cellular fitness. To maintain the proteome functional proteins are under the constant surveillance of dedicated molecular chaperones that perform protein quality control (PQC). Using the model organism yeast Saccharomyces cerevisiae this thesis investigates the molecular mechanisms that cells employ to maintain protein homeostasis (proteostasis). In Study I the role of the molecular chaperone Hsp110 in the disentanglement and reactivation of aggregated proteins was investigated. We found that Hsp110 is essential for cellular protein disaggregation driven by the molecular chaperones Hsp40, Hsp70 and Hsp104 and characterized its involvement via regulation of Hsp70 ATPase activity as a nucleotide exchange factor. In Study II we found out that Hsp110 undergoes translational frameshifting during its expression resulting in a nuclear targeting. Nuclear Hsp110 interacts with Hsp70 and reprograms the proteostasis system to better deal with stress and to confer longevity. Study III describes regulation of Hsp70 function in PQC by the nucleotide exchange factor Fes1. We found that rare alternative splicing regulates Fes1 subcellular localization in the cytosol and nucleus and that the cytosolic isoform has a key role in PQC. In Study IV we have revealed the molecular mechanism that Fes1 employ in PQC. We show that Fes1 carries a specialized release domain (RD) that ensures the efficient release of protein substrates from Hsp70, explaining how Fes1 maintains the Hsp70-chaperone system clear of persistent misfolded proteins. In Study V we report on the use of a novel bioluminescent reporter (Nanoluc) for use in yeast to measure the gene expression and protein levels. In summary, this thesis contributes to the molecular understanding of chaperone-dependent PQC mechanisms both at the level of individual components as well as how they interact to ensure proteostasis.
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| 35. |
- Kampinga, Harm H., et al.
(författare)
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Function, evolution, and structure of J-domain proteins
- 2019
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Ingår i: Cell stress & chaperones (Print). - : Springer Science and Business Media LLC. - 1355-8145 .- 1466-1268. ; 24:1, s. 7-15
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Forskningsöversikt (refereegranskat)abstract
- Hsp70 chaperone systems are very versatile machines present in nearly all living organisms and in nearly all intracellular compartments. They function in many fundamental processes through their facilitation of protein (re)folding, trafficking, remodeling, disaggregation, and degradation. Hsp70 machines are regulated by co-chaperones. J-domain containing proteins (JDPs) are the largest family of Hsp70 co-chaperones and play a determining role functionally specifying and directing Hsp70 functions. Many features of JDPs are not understood; however, a number of JDP experts gathered at a recent CSSI-sponsored workshop in Gdansk (Poland) to discuss various aspects of J-domain protein function, evolution, and structure. In this report, we present the main findings and the consensus reached to help direct future developments in the field of Hsp70 research.
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| 36. |
- Kandasamy, Ganapathi, et al.
(författare)
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Hsp70-Hsp110 chaperones deliver ubiquitin-dependent and -independent substrates to the 26S proteasome for proteolysis in yeast
- 2018
-
Ingår i: Journal of Cell Science. - : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 131:6
-
Tidskriftsartikel (refereegranskat)abstract
- During protein quality control, proteotoxic misfolded proteins are recognized by molecular chaperones, ubiquitylated by dedicated quality control ligases and delivered to the 26S proteasome for degradation. Proteins belonging to the Hsp70 chaperone and Hsp110 (the Hsp70 nucleotide exchange factor) families function in the degradation of misfolded proteins by the ubiquitin-proteasome system via poorly understood mechanisms. Here, we report that the Saccharomyces cerevisiae Hsp110 proteins (Sse1 and Sse2) function in the degradation of Hsp70-associated ubiquitin conjugates at the post-ubiquitylation step and are also required for ubiquitin-independent proteasomal degradation. Hsp110 associates with the 19S regulatory particle of the 26S proteasome and interacts with Hsp70 to f acilitate the delivery of Hsp70 substrates for proteasomal degradation. By using a highly defined ubiquitin-independent proteasome substrate, we show that the mere introduction of a single Hsp70-binding site renders its degradation dependent on Hsp110. The findings define a dedicated and chaperone-dependent pathway for the efficient shuttling of cellular proteins to the proteasome with profound implications for understanding protein quality control and cellular stress management.
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| 37. |
- Kohler, Verena, et al.
(författare)
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Hsp70-mediated quality control : should I stay or should I go?
- 2020
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Ingår i: Biological chemistry (Print). - : Walter de Gruyter GmbH. - 1431-6730 .- 1437-4315. ; 401:11, s. 1233-1248
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Forskningsöversikt (refereegranskat)abstract
- Chaperones of the 70 kDa heat shock protein (Hsp70) superfamily are key components of the cellular proteostasis system. Together with its co-chaperones, Hsp70 forms proteostasis subsystems that antagonize protein damage during physiological and stress conditions. This function stems from highly regulated binding and release cycles of protein substrates, which results in a flow of unfolded, partially folded and misfolded species through the Hsp70 subsystem. Specific factors control how Hsp70 makes decisions regarding folding and degradation fates of the substrate proteins. In this review, we summarize how the flow of Hsp70 substrates is controlled in the cell with special emphasis on recent advances regarding substrate release mechanisms.
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| 38. |
- Kohler, Verena, 1992-, et al.
(författare)
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Nuclear Hsp104 safeguards the dormant translation machinery during quiescence
- 2024
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- The resilience of cellular proteostasis declines with age, which drives protein aggregation and compromises viability. The nucleus has emerged as a key quality control compartment that handles misfolded proteins produced by the cytosolic protein biosynthesis system. Here, we find that age-associated metabolic cues target the yeast protein disaggregase Hsp104 to the nucleus to maintain a functional nuclear proteome during quiescence. The switch to respiratory metabolism and the accompanying decrease in translation rates direct cytosolic Hsp104 to the nucleus to interact with latent translation initiation factor eIF2 and to suppress protein aggregation. Hindering Hsp104 from entering the nucleus in quiescent cells results in delayed re-entry into the cell cycle due to compromised resumption of protein synthesis. In sum, we report that cytosolic-nuclear partitioning of the Hsp104 disaggregase is a critical mechanism to protect the latent protein synthesis machinery during quiescence in yeast, ensuring the rapid restart of translation once nutrients are replenished.
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| 39. |
- Kohler, Verena, 1992-, et al.
(författare)
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Reversible protein assemblies in the proteostasis network in health and disease
- 2023
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Ingår i: Frontiers in Molecular Biosciences. - : Frontiers Media S.A.. - 2296-889X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- While proteins populating their native conformations constitute the functional entities of cells, protein aggregates are traditionally associated with cellular dysfunction, stress and disease. During recent years, it has become clear that large aggregate-like protein condensates formed via liquid-liquid phase separation age into more solid aggregate-like particles that harbor misfolded proteins and are decorated by protein quality control factors. The constituent proteins of the condensates/aggregates are disentangled by protein disaggregation systems mainly based on Hsp70 and AAA ATPase Hsp100 chaperones prior to their handover to refolding and degradation systems. Here, we discuss the functional roles that condensate formation/aggregation and disaggregation play in protein quality control to maintain proteostasis and why it matters for understanding health and disease.
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| 40. |
- Löfdahl, Claes-Göran, et al.
(författare)
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Cost effectiveness of budesonide/formoterol in a single inhaler for COPD compared with each monocomponent used alone
- 2005
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Ingår i: PharmacoEconomics. - 1179-2027. ; 23:4, s. 365-375
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To compare the healthcare costs and effects of budesonide/formoterol in,a single inhaler with those of budesonide and formoterol monotherapies, and placebo, in a multinational study in patients with chronic obstructive pulmonary disease (COPD), National Heart, Lung and Blood Institute (NHLBI)/WHO Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages III or IV. Previous analysis of the clinical data from the study had shown that budesonide/formoterol was associated with better lung function and improved health-related QOL compared with the monocomponents or placebo and lower frequency of exacerbations compared with formoterol and placebo. Method: Patients (n = 1022) were randomised to twice-daily treatment with two inhalations of budesonide/formoterol (160 mu g/4.5 mu g) in a single inhaler, budesonide 200 mu g, formoterol 4.5 mu g or placebo for 12 months. Data on medication and healthcare use were combined with Swedish unit cost data to estimate the total annual healthcare cost per patient from the Swedish healthcare payer perspective. Costs were valued in Swedish kronor (SEK) [2001 values] and converted to euros (SEK1 = E0.11, 25th April 2003). Results: This evaluation estimated the total annual healthcare costs per patient to be numerically lower for budesonide/formoterol (E2518) than for budesonide (E3194), formoterol (E3653) or placebo (E3213). Cost-effectiveness acceptability curves suggest that budesonide/formoterol may be cost effective compared with formoterol, even if the decision maker is not willing to pay anything for the additional clinical effects, and that budesonide/formoterol is cost effective compared with placebo if a decision maker is willing to pay about E2 per day, per avoided exacerbation. Conclusion: This economic analysis suggests that the clinical benefits of using budesonide/formoterol in a single inhaler are achieved at a numerically lower total healthcare cost than either monocomponent or placebo. Budesonide/formoterol in patients with severe COPD (GOLD stages III or IV) may be cost effective, from the healthcare provider perspective, compared with either monocomponent.
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| 41. |
- Malm, Eva, et al.
(författare)
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Alteration of rod and cone function in children with Usher syndrome
- 2011
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Ingår i: European Journal of Ophthalmology. - Milan, Italy : Wichtig Editore Srl. - 1120-6721 .- 1724-6016. ; 21:1, s. 30-38
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate the retinal function, with emphasis on phenotype and rate of progression, in infants and children with different genotypes of Usher syndrome.Methods: Fourteen children (2-10 years of age) with retinitis pigmentosa and hearing impairment were examined with full-field electroretinography (ERG) during general anesthesia, ophthalmologic examination, and genetic analysis. Five children were repeatedly examined (follow-up 5-10 years) with full-field ERG under local anesthesia and in 2 children multifocal ERG and optical coherence tomography (OCT) were performed. These results were compared to full-field ERG data from 58 children without retinal eye disorder.Results: Six children were genotyped as Usher 1B, 2A, and 3A. Full-field ERG demonstrated early alterations corresponding to a rod-cone dystrophy in all children. A remaining rod function could be verified in the majority of the children up to 4 years of age. After 4 years of age, there was a further deterioration of the rod function; the progress was severe in Usher types 1 and 2 and moderate in Usher type 3. In all children, the cone function was moderately reduced, in a few cases almost normal. The results from the 58 children without retinal disorder confirm that full-field ERG during general anesthesia is reliable. Multifocal ERG confirmed a preserved central cone function and in OCT there were discrete structural alterations.Conclusions: Full-field ERG during general anesthesia in children with Usher syndrome demonstrates variable phenotypes and different degrees in rate of progression during childhood.
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| 42. |
- Malm, Eva, et al.
(författare)
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Full-field electroretinography and marked variability in clinical phenotype of Alström syndrome
- 2008
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Ingår i: Archives of ophthalmology (1960). - Chicago : American medical association. - 0003-9950. ; 126:1, s. 51-57
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To characterize the clinical phenotype and to study the course of disease in patients with Alström syndrome, with an emphasis on retinal function assessed with full-field electroretinography (ERG). METHODS: Three age- and sex-matched patients with Alström syndrome were selected from our retinitis pigmentosa register for repeated ophthalmologic examinations that included tests for color vision and visual fields using Goldmann perimetry and for repeated assessment of full-field ERGs. RESULTS: Electroretinography demonstrated cone-rod degeneration in all 3 patients. A concomitant impairment of color vision and visual fields was also observed as well as marked variation in retinal function and in disease severity. CONCLUSIONS: Full-field ERGs confirmed that Alström syndrome is associated with a cone-rod type of retinal degeneration. In this study, we have shown a striking variability in retinal function and disease onset and severity, which has, to our knowledge, not been described previously in Alström syndrome.
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| 43. |
- Malm, Eva, et al.
(författare)
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Phenotypes in defined genotypes including siblings with Usher syndrome
- 2011
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Ingår i: Ophthalmic Genetics. - : Informa Healthcare. - 1381-6810 .- 1744-5094. ; 32:2, s. 65-74
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To characterize visual function in defined genotypes including siblings with Usher syndrome.METHODS: Thirteen patients with phenotypically different subtypes of Usher syndrome, including 3 families with affected siblings, were selected. Genetic analysis and ophthalmological examinations including visual fields, full-field electroretinography (ERG), multifocal electroretinography (mf ERG), and optical coherence tomography (OCT) were assessed. The patients' degree of visual handicap was evaluated by a questionnaire (ADL).RESULTS: Twelve of thirteen patients were genotyped as Usher 1B, 1D, 1F, 2A, 2C or 3A. In 12 of 13 patients examined with ERG the 30 Hz flickering light response revealed remaining cone function. In 3 of the patients with Usher type 1 mf ERG demonstrated a specific pattern, with a sharp distinction between the area with reduced function and the central area with remaining macular function and normal peak time. OCT demonstrated loss of foveal depression with distortion of the foveal architecture in the macula in all patients. The foveal thickness ranged from 159 to 384 µm and was not correlated to retinal function. Three siblings shared the same mutation for Usher 2C but in contrast to previous reports regarding this genotype, 1 of them diverged in phenotype with substantially normal visual fields, almost normal OCT and mf ERG findings, and only moderately reduced rod and cone function according to ERG.CONCLUSIONS: Evaluation of visual function comprising both the severity of the rod cone degeneration and the function in the macular region confirm phenotypical heterogeneity within siblings and between different genotypes of Usher syndrome.
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| 44. |
- Martins, António, et al.
(författare)
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Ssy5 is a signaling serine protease that exhibits atypical biogenesis and marked S1 specificity
- 2018
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Ingår i: Journal of Biological Chemistry. - : AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC. - 0021-9258 .- 1083-351X. ; 293:22, s. 8362-8378
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Tidskriftsartikel (refereegranskat)abstract
- Ssy5 is a signaling endoprotease that plays a key role in regulating central metabolism, cellular aging, and morphological transitions important for growth and survival of yeast (Saccharomyces cerevisiae) cells. In response to extracellular amino acids, Ssy5 proteolytically activates the transcription factors Stp1 and Stp2, leading to enhanced Ssy1-Ptr3-Ssy5 (SPS) sensor-regulated gene expression. Ssy5 comprises a catalytic (Cat) domain and an extensive regulatory prodomain. Ssy5 is refractory to both broad-spectrum and serine protease-specific inhibitors, confounding its classification as a protease, and no information about Ssy5's cleavage-site preferences and its mechanism of substrate selection is available. Here, using mutational and inhibition experiments, we investigated the biogenesis and catalytic properties of Ssy5 and conclusively show that it is a serine protease. Atypical for the majority of serine proteases, Ssy5's prodomain was obligatorily required in cis during biogenesis for the maturation of the proteolytic activity of the Cat domain. Autolysis and Stp1 and Stp2 cleavage occurred between a cysteine (at the P1 site) and a serine or alanine (at the P1 site) and required residues with short side chains at the P1 site. Substitutions in the Cat domain affecting substrate specificity revealed that residues Phe-634, His-661, and Gly-671 in the S1-binding pocket of this domain are important for Ssy5 catalytic function. This study confirms that the signaling protease Ssy5 is a serine protease and provides a detailed understanding of the biogenesis and intrinsic properties of this key enzyme in yeast.
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| 45. |
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| 46. |
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| 47. |
- Masser, Anna E., 1987-
(författare)
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Controlling protein homeostasis through regulation of Heat shock factor 1
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In order to thrive in a changing environment all organisms need to ensure protein homeostasis (proteostasis). Proteostasis is ensured by the proteostasis system that monitors the folding status of the proteome and regulates cell physiology and gene expression to counteract any perturbations. An increased burden on the proteostasis system activates Heat shock factor 1 (Hsf1) to induce transcription of the heat shock response (HSR), a transiently induced transcriptional program including core proteostasis genes, importantly those encoding the Hsp70 class of molecular chaperones. The HSR assists cells in counteracting the harmful effects of protein folding stress and restoring proteostasis. The work presented in this thesis is based on experiments with the Saccharomyces cerevisiae (yeast) model with the overall goal of deciphering how Hsp70 detects and impacts on perturbations of cellular proteostasis and controls Hsf1 activity.In Study I we describe the fundamental mechanism by which Hsp70 maintains Hsf1 in its latent state by controlling its ability to bind DNA. We found that Hsf1 and unfolded proteins directly compete for binding to the Hsp70 substrate-binding domain. During heat shock the pool of unfolded proteins mainly consist of misfolded, newly synthesized proteins. Severe out-titration of Hsp70 by misfolded substrates resulted in unrestrained Hsf1 activity inducing a previously uncharacterized genetic hyper-stress program. More insight into regulation of Hsp70 availability was gained in Study II where the two splice isoforms of the Hsp70 nucleotide exchange factor Fes1 were characterized. We found that the cytosolic splice isoform Fes1S is crucial to release unfolded proteins from Hsp70 and that impaired release results in strong Hsf1 activation.In Study III we developed methodology to easily measure the rapid changes in Hsf1 activity upon proteostatic perturbations and to monitor protein turnover using the novel bioluminescent reporter NanoLuc optimized for yeast expression (yNluc). In Study IV we report that yNluc also functions as an in vivo reporter that detects severe perturbations of de novo protein folding by its failure to fold to an active conformation under such conditions.Finally, in Study V we investigated how organellar proteostasis impacts on the availability of cytosolic Hsp70. We found that a lowered mitochondrial proteostatic load as a result of high translation accuracy extended lifespan and improved cytosolic proteostasis capacity, evidenced by more rapid stress recovery and less sensitivity to toxic misfolded proteins. In contrast, lowered mitochondrial translation accuracy decreased lifespan and impaired management of cytosolic protein aggregates as well as elicited a general transcriptional stress response.Taken together, the findings presented in this thesis advance our understanding of how the regulatory mechanisms of the proteostasis system function. Furthermore, they provide novel methodology that will facilitate future studies to improve our understanding how cells integrate internal and external stress cues to control proteostasis.
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| 48. |
- Masser, Anna E., et al.
(författare)
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Cytoplasmic protein misfolding titrates Hsp70 to activate nuclear Hsf1
- 2019
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Ingår i: eLIFE. - 2050-084X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Hsf1 is an ancient transcription factor that responds to protein folding stress by inducing the heat-shock response (HSR) that restore perturbed proteostasis. Hsp70 chaperones negatively regulate the activity of Hsf1 via stress-responsive mechanisms that are poorly understood. Here, we have reconstituted budding yeast Hsf1-Hsp70 activation complexes and find that surplus Hsp70 inhibits Hsf1 DNA-binding activity. Hsp70 binds Hsf1 via its canonical substrate binding domain and Hsp70 regulates Hsf1 DNA-binding activity. During heat shock, Hsp70 is out-titrated by misfolded proteins derived from ongoing translation in the cytosol. Pushing the boundaries of the regulatory system unveils a genetic hyperstress program that is triggered by proteostasis collapse and involves an enlarged Hsf1 regulon. The findings demonstrate how an apparently simple chaperone-titration mechanism produces diversified transcriptional output in response to distinct stress loads.
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| 49. |
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| 50. |
- Masser, Anna E., et al.
(författare)
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Hsf1 on a leash - controlling the heat shock response by chaperone titration
- 2020
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Ingår i: Experimental Cell Research. - : Elsevier BV. - 0014-4827 .- 1090-2422. ; 396:1
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Forskningsöversikt (refereegranskat)abstract
- Heat shock factor 1 (Hsf1) is an ancient transcription factor that monitors protein homeostasis (proteostasis) and counteracts disturbances by triggering a transcriptional programme known as the heat shock response (HSR). The HSR is transiently activated and upregulates the expression of core proteostasis genes, including chaperones. Dysregulation of Hsf1 and its target genes are associated with disease; cancer cells rely on a constitutively active Hsf1 to promote rapid growth and malignancy, whereas Hsf1 hypoactivation in neurodegenerative disorders results in formation of toxic aggregates. These central but opposing roles highlight the importance of understanding the underlying molecular mechanisms that control Hsf1 activity. According to current understanding, Hsf1 is maintained latent by chaperone interactions but proteostasis perturbations titrate chaperone availability as a result of chaperone sequestration by misfolded proteins. Liberated and activated Hsf1 triggers a negative feedback loop by inducing the expression of key chaperones. Until recently, Hsp90 has been highlighted as the central negative regulator of Hsf1 activity. In this review, we focus on recent advances regarding how the Hsp70 chaperone controls Hsf1 activity and in addition summarise several additional layers of activity control.
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