| 1. |
- Ahlner, Alexandra, 1984-, et al.
(författare)
-
Conformational Dynamics and Multimerization of Active Forms of the EphrinB Receptor 2 Kinase Domain
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Active and autoinhibited forms of the ephrinB receptor 2 (EphB2) kinase domain have been studied using NMR spectroscopy. The project was initiated because of the finding that the crystal structures of active forms of the kinase domain and previous NMR studies suggested that a change in inter-lobe flexibility and the sampling of catalytically competent excited states conformations are responsible for activity. Using Carr-Purcell-Meiboom-Gill relaxation dispersion experiments, we have measured millisecond dynamics to identify such states. We have also performed concentration dependent relaxation experiments and analytical ultracentrifugation experiments that report on the effective protein size to look for possible differences in self-association for active and autoinhibited forms of the EphB2 kinase domain. We show that the active but not autoinhibited forms exchange between a ground state and an excited state at a rate of 1900 s-1. Similar results were found for the S677/680A mutant of the protein. The nature and importance of the excited state is still unknown. Our most important finding is that active forms of the kinase domain self-associate in a concentration dependent manner and form tetramers and possibly larger oligomers. Multimerization of the kinase domain may enable the assembly of complexes of downstream proteins and could be important for Eph signaling.
|
|
| 2. |
- Andrésen, Cecilia, et al.
(författare)
-
Transient structure and dynamics in the disordered c-Myc transactivation domain affect Bin1 binding
- 2012
-
Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP): Policy C / Oxford University Press. - 0305-1048 .- 1362-4962. ; 40:13, s. 6353-6366
-
Tidskriftsartikel (refereegranskat)abstract
- The crucial role of Myc as an oncoprotein and as a key regulator of cell growth makes it essential to understand the molecular basis of Myc function. The N-terminal region of c-Myc coordinates a wealth of protein interactions involved in transformation, differentiation and apoptosis. We have characterized in detail the intrinsically disordered properties of Myc-1-88, where hierarchical phosphorylation of S62 and T58 regulates activation and destruction of the Myc protein. By nuclear magnetic resonance (NMR) chemical shift analysis, relaxation measurements and NOE analysis, we show that although Myc occupies a very heterogeneous conformational space, we find transiently structured regions in residues 22-33 and in the Myc homology box I (MBI; residues 45-65); both these regions are conserved in other members of the Myc family. Binding of Bin1 to Myc-1-88 as assayed by NMR and surface plasmon resonance (SPR) revealed primary binding to the S62 region in a dynamically disordered and multivalent complex, accompanied by population shifts leading to altered intramolecular conformational dynamics. These findings expand the increasingly recognized concept of intrinsically disordered regions mediating transient interactions to Myc, a key transcriptional regulator of major medical importance, and have important implications for further understanding its multifaceted role in gene regulation.
|
|
| 3. |
- Andrésen, Cecilia, et al.
(författare)
-
Transient structure and intrinsic disorder in the c-Myc transactivation domain and its effects on ligand binding
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The crucial role of c-Myc as an oncoprotein and as a key regulator of cell growth makes it essential to understand the molecular basis of c-Myc function. The transactivation domain of c-Myc coordinates a wealth of protein interactions involved in transformation, differentiation and apoptosis. We have characterized in detail the intrinsically disordered properties of c-Myc-1-88, where hierarchical phosphorylation of T58 and S62 regulates activation and destruction of the c-Myc protein. By NMR chemical shift analysis, relaxation measurements and NOE analysis, we show that both the MBI region (residues 45-65) and residues 22-33 are transiently structured regions, conserved also in other members of the Myc family. Binding of Bin1-SH3 to c-Myc-1-88 as assayed by NMR and SPR revealed primary binding to the S62 region, but also a dynamically disordered and multivalent complex in which intrinsic disorder of c-Myc-1-88 was retained while releasing transient intramolecular interactions. Our findings describe a novel mode of regulatory recognition of c-Myc that is in agreement with the increasingly recognized capability of intrinsically disordered regions to efficiently mediate transient interactions with a wide range of targets, with important implications towards understanding the unique multifaceted biological functions of c-Myc.
|
|
| 4. |
- Csizmok, Veronika, et al.
(författare)
-
Multivalent Interactions with Fbw7 and Pin1 Facilitate Recognition of c-Jun by the SCFFbw7 Ubiquitin Ligase
- 2018
-
Ingår i: Structure. - : CELL PRESS. - 0969-2126 .- 1878-4186. ; 26:1, s. 28-
-
Tidskriftsartikel (refereegranskat)abstract
- Many regulatory proteins, including the transcription factor c-Jun, are highly enriched in disordered protein regions that govern growth, division, survival, differentiation, and response to signals. The stability of c-Jun is controlled by poorly understood regulatory interactions of its disordered region with both the E3 ubiquitin ligase SCFFbw7 and prolyl cis-trans isomerase Pin1. We use nuclear magnetic resonance and fluorescence studies of c-Jun to demonstrate that multisite c-Jun phosphorylation is required for high-affinity interaction with Fbw7. We show that the Pin1 WW and PPIase domains interact in a dynamic complex with multiply phosphorylated c-Jun. Importantly, Pin1 isomerizes a pSer-Pro peptide bond at the c-Jun N terminus that affects binding to Fbw7 and thus modulates the ubiquitin-mediated degradation of c-Jun. Our findings support the general principle that multiple weak binding motifs within disordered regions can synergize to yield high-affinity interactions and provide rapidly evolvable means to build and fine-tune regulatory events.
|
|
| 5. |
- Greve, Anders M., et al.
(författare)
-
Effect Modifications of Lipid-Lowering Therapy on Progression of Aortic Stenosis (from the Simvastatin and Ezetimibe in Aortic Stenosis [SEAS] Study)
- 2018
-
Ingår i: American Journal of Cardiology. - : Elsevier. - 0002-9149 .- 1879-1913. ; 121:6, s. 739-745
-
Tidskriftsartikel (refereegranskat)abstract
- Observational studies indicate that low-density lipoprotein (LDL) cholesterol acts as a primary contributor to an active process leading to aortic stenosis (AS) development. However, randomized clinical trials have failed to demonstrate an effect of lipid lowering on impeding AS progression. This study explored if pretreatment LDL levels and AS severity altered the efficacy of lipid-lowering therapy. The study goal was evaluated in the analysis of surviving patients with baseline data in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) trial of 1,873 asymptomatic patients with mild-to-moderate AS. Serially measured peak aortic jet velocity was the primary effect estimate. Linear mixed model analysis adjusted by baseline peak jet velocity and pretreatment LDL levels was used to assess effect modifications of treatment. Data were available in 1,579 (84%) patients. In adjusted analyses, lower baseline peak aortic jet velocity and higher pretreatment LDL levels increased the effect of randomized treatment (p >= 0.04 for interaction). As such, treatment impeded progression of AS in the highest quartile of LDL among patients with mild AS at baseline (0.06 m/s per year slower progression vs placebo in peak aortic jet velocity, 95% confidence interval 0.01 to 0.11, p = 0.03), but not in the 3 other quartiles of LDL. Conversely, among patients with moderate AS, there was no detectable effect of treatment in any of the pretreatment LDL quartiles (all p In conclusion, in a non prespecified post hoc analysis, the efficacy of lipid-lowering therapy on impeding AS progression increased with higher pretreatment LDL and lower peak aortic jet velocity (SEAS study: NCT00092677).
|
|
| 6. |
|
|
| 7. |
- Hodges, Gethin W., et al.
(författare)
-
Effect of simvastatin and ezetimibe on suPAR levels and outcomes
- 2018
-
Ingår i: Atherosclerosis. - : ELSEVIER IRELAND LTD. - 0021-9150 .- 1879-1484. ; 272, s. 129-136
-
Tidskriftsartikel (refereegranskat)abstract
- Background and aims: Soluble urokinase plasminogen activator receptor (suPAR) is an inflammatory marker associated with cardiovascular disease. Statins lower both low-density lipoprotein (LDL)-cholesterol and C-reactive protein (CRP), resulting in improved outcomes. However, whether lipid-lowering therapy also lowers suPAR levels is unknown.& para;& para;Methods: We investigated whether treatment with Simvastatin 40 mg and Ezetimibe 10 mg lowered plasma suPAR levels in 1838 patients with mild-moderate, asymptomatic aortic stenosis, included in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study, using a pattern mixture model. A 1-year Cox analysis, adjusted for established cardiovascular risk factors, allocation to study treatment, peak aortic valve velocity and baseline suPAR, was performed to evaluate relationships between change in suPAR with all-cause mortality and the composite endpoint of major cardiovascular events (MCE) composed of ischemic cardiovascular events (ICE) and aortic valve related events (AVE).& para;& para;Results: After 4.3 years of follow-up, suPAR levels had increased by 9.2% (95% confidence interval [CI]: 7.0%-11.5%) in the placebo group, but only by 4.1% (1.9%-6.2%) in the group with lipid-lowering treatment (p<0.001). In a multivariate 1-year analysis, 1-year suPAR was strongly associated with all-cause mortality, hazard ratio (HR) = 2.05 (1.17-3.61); MCE 1.40 (1.01-1.92); and AVE 1.42 (1.02-1.99) (all p<0.042) for each doubling of suPAR; but was not associated with ICE.& para;& para;Conclusions: Simvastatin and Ezetimibe treatment impeded the progression of the time-related increase in plasma suPAR levels. Year-1 suPAR was associated with all-cause mortality, MCE, and AVE irrespective of baseline levels (SEAS study: NCT00092677). (C) 2018 Elsevier B.V. All rights reserved.
|
|
| 8. |
- Knorr, Ulla, et al.
(författare)
-
Alzheimer's disease related biomarkers in bipolar disorder - A longitudinal one-year case-control study.
- 2022
-
Ingår i: Journal of affective disorders. - : Elsevier BV. - 1573-2517 .- 0165-0327. ; 297, s. 623-633
-
Tidskriftsartikel (refereegranskat)abstract
- Bipolar disorder (BD) is a heterogeneous mental disorder characterized by recurrent relapses of affective episodes: Subgroups of patients with BD have cognitive deficits, and an increased risk of dementia.This prospective, longitudinal, one-year follow-up, case-control study investigated biomarkers for AD and neurodegenerative diseases, namely: cerebrospinal fluid (CSF) amyloid beta (Aβ) isoforms and ratios (Aβ42, Aβ40, Aβ38), CSF soluble amyloid precursor protein (sAPP) α and β, CSF total (t-tau) and phosphorylated tau (p-tau), CSF neurofilament-light (NF-L), CSF neurogranin (NG), plasma-isoforms Aβ42 and Aβ40, plasma-tau, plasma-NF-L, and serum S100B, in patients with BD (N=62, aged 18-60) and gender-and-age-matched healthy control individuals (N=40). CSF and plasma/serum samples were collected at baseline, during and after an affective episode, if it occurred, and after a year. Data were analyzed in mixed models.Levels of CSF Aβ42 decreased in patients with BD who had an episode during follow-up (BD-E) (N=22) compared to patients without an episode (BD-NE) (N=25) during follow-up (P=0.002). Stable levels were seen for all other markers in BD-E compared to BD-NE during the one-year follow-up. We found no statistically significant differences between patients with BD and HC at T0 and T3 for Aβ42, Aβ40, Aβ38, Aβ42/38, Aβ42/40, sAPPα, sAPPβ, t-tau, p-tau, p-tau /t-tau, NF-L, NG in CSF and further Aβ40, Aβ42, Aβ42/40, t-tau, NF-L in plasma, S100B in serum, and APOE-status. Furthermore, all 18 biomarkers were stable in HC during the one-year follow-up from T0 to T3.A panel of biomarkers of Alzheimer's and neurodegeneration show no differences between patients with BD and HC. There were abnormalities of amyloid production/clearance during an acute BD episode. The abnormalities mimic the pattern seen in AD namely decreasing CSF Aβ42 and may suggest an association with brain amyloidosis.
|
|
| 9. |
- Knorr, Ulla, et al.
(författare)
-
Biomarkers for neurodegeneration impact cognitive function: a longitudinal 1-year case–control study of patients with bipolar disorder and healthy control individuals
- 2024
-
Ingår i: International Journal of Bipolar Disorders. - 2194-7511. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Abnormalities in cerebrospinal fluid (CSF)-amyloid-beta (Aβ)42, CSF-Aβ40, CSF-Aβ38, CSF-soluble amyloid precursor proteins α and β, CSF-total-tau, CSF-phosphorylated-tau, CSF-neurofilament light protein (NF-L), CSF-neurogranin, plasma-Aβ42, plasma-Aβ40, plasma-total-tau, plasma-NF-L and, serum-S100B during affective episodes may reflect brain changes that could impact cognitive function in patients with bipolar disorder (BD). The study aimed to investigate the association between these biomarkers indicative of Alzheimer’s disease and those reflecting neurodegeneration alongside their impact on cognitive function in patients with BD and healthy control individuals (HC). The primary hypothesis was that GL and VL would increase with increasing levels of CSF-Aβ42 based on data from T0 and T3 in BD and HC jointly. Methods: In a prospective, longitudinal case–control study euthymic patients with BD (N = 85) and HC (N = 44) were evaluated with clinical assessment and neuropsychological testing at baseline (T0) and during euthymia after a year (T3). Patients’ affective states were recorded weekly as euthymic, subthreshold level, major depression, or (hypo)mania. If an episode occurred during follow-up, the patient was also assessed in post-episode euthymia. Cognitive performance was measured as a global cognitive score (GL) for four cognitive domains including verbal learning and memory (VL). Results: Estimated in a linear mixed model GL increased with 0.001 for each increase of 1pg/ml of CSF-Aβ42 (97.5%, CI 0.00043–0.0018, adjusted-p = 0.0005) while VL increased by 0.00089 (97.5%, CI 0.00015–0.0018, adjusted-p = 0.045) in BD and HC jointly. The association was weak, however stronger in patients with BD compared to HC. Associations between other biomarkers including CSF-neurogranin, and cognitive domains were overall weak, and none remained significant after adjustment for multiple testing. Limitations: Modest sample size. A complete data set regarding both CSF-AB-42 and cognitive test scores was obtained from merely 61 patients with BD and 38 HC individuals. Conclusion: CSF-Aβ42 may be associated with cognitive dysfunction in patients with BD and HC individuals. The association appeared to be stronger in BD but with overlapping confidence intervals. Hence it remains uncertain whether the association is a general phenomenon or driven by BD.
|
|
| 10. |
- Knorr, Ulla, et al.
(författare)
-
Cerebrospinal fluid synaptic biomarker changes in bipolar disorder - A longitudinal case-control study.
- 2024
-
Ingår i: Journal of affective disorders. - 1573-2517. ; 358, s. 250-259
-
Tidskriftsartikel (refereegranskat)abstract
- This exploratory study investigated cerebrospinal fluid (CSF) synaptic protein biomarkers in bipolar disorder (BD), aiming to highlight the neurobiological basis of the disorder. With shared cognitive impairment features between BD and Alzheimer's disease, and considering increased dementia risk in BD patients, the study explores potential connections.Fifty-nine well-characterized patients with BD and thirty-seven healthy control individuals were examined and followed for one year. Synaptic proteins encompassing neuronal pentraxins (NPTX)1, NPTX2, and NPTX-receptor, 14-3-3 protein family epsilon, and zeta/delta, activating protein-2 complex subunit beta, synucleins beta-synuclein and gamma-synuclein, complexin-2, phosphatidylethanolamine-binding protein 1, rab GDP dissociation inhibitor alpha, and syntaxins 1B and 7 were measured in CSF using a microflow liquid chromatography-mass spectrometric multiple reaction monitoring set-up. Biomarker levels were compared between BD and HC and in BD before, during, and after mood episodes.The synaptic proteins revealed no statistically significant differences between BD and HC, neither at baseline, one-year follow-up, or in terms of changes from baseline to follow-up. Moreover, the CSF synaptic protein levels in patients with BD were unaltered compared to baseline when they stabilized in euthymia following an affective episode and at one-year follow-up.It is uncertain what the CSF biomarker concentrations reflect since we yet do not know the mechanisms of release of these proteins, and we are uncertain of what increased or decreased levels reflect.This first-ever investigation of a panel of CSF protein biomarkers of synaptic dysfunction in patients with BD and HC individuals found no statistically significant differences cross-sectionally or longitudinally.
|
|
