x What Boris Johnson’s Big Win Means for Brexit and Scotland By feedproxy.google.com Published On :: Fri, 13 Dec 2019 14:25:22 +0000 13 December 2019 Thomas Raines Director, Europe Programme @TomHRaines Google Scholar Jason Naselli Senior Digital Editor LinkedIn Thomas Raines tells Jason Naselli about the impact the large Conservative majority will have on the next phase of Brexit negotiations and Scotland’s place in the United Kingdom. 2019-12-13-Johnson.jpg Boris Johnson speaks after the Conservatives secured a majority in the UK general election. Photo: Getty Images. What does the UK election result mean for Brexit and forthcoming trade negotiations with the EU?The most important thing is that it means Brexit will definitely happen. Since the referendum, we’ve had three-and-a-half years of continued uncertainty where all outcomes were still possible. We now know that Brexit will become irreversible from 31 January.That’s the biggest thing, because I think that will have a big psychological impact on politics, both in the UK and also on the EU side. The EU has been working with a partner that has been unsure about its direction, and perhaps some had still hoped that the process might still be reversed, but that direction is now completely clear.Obviously the first order of business is to pass the withdrawal agreement, which should be pretty straightforward given the majority that the Conservatives have. That’s a formality now.Then, the question becomes about the level of ambition for the next year. It is an exceptionally ambitious timetable to negotiate, ratify and implement a new relationship before the end of the transition period in December 2020.What is achievable by the end of next year? I think there are three possible outcomes here. One: that timetable doesn’t work and Boris Johnson follows through on his pledge to leave the transition period anyway, leading to a ‘no trade deal’ outcome.Two: the negotiations are able to deliver something by the end of 2020, either because the depth and ambition of any agreement is relatively low level (what Michel Barnier has called a ‘vital minimum’) and/or because they come up with some type of compromise on the process which is not called an extension, but something else: a type of temporary agreement or a new implementation period.This is a situation where you might have a bare-bones agreement for the end of the transition period, but with an extended period of negotiation for different unresolved issues. The EU will probably insist upon level playing field guarantees and fishing access rights as a component of any such agreement.Three: Boris Johnson breaks his manifesto pledge not to extend the transition. Now, he has stared down the barrel of leaving with no deal before and he made a political judgment that it was better to make significant compromises on his negotiating position than to follow through with ‘no deal’. I suspect he might make that same judgment again.No option is ideal. The first is the most economically disruptive, the second means the EU will be in an even stronger position to dictate terms and the third means breaking a manifesto pledge.How important is that end of transition deadline now? It was an important issue for the Brexit Party and hardliners in the European Research Group of Conservative MPs. But given the size of a majority, he may need to worry less about them. Is the transition deadline that important to people who voted Conservative, especially if he can show that he has taken the UK out of the EU by the end of January?I think there may indeed be some political space for Johnson here, given the size of his majority and given that the first phase of Brexit will have been done, along with the debate about withdrawal.There will be a lot of difficult, technical negotiations in all sorts of areas, some of which I think will become quite rancorous, but won’t necessarily become front page news in the way some of the first phase of negotiations has, not least because you won’t have the theatre of a hung parliament.Hopefully, there will be more focus on the substance of the agreement, and the debate will be about the consequences of divergence versus staying more aligned with the EU, which is basically the central question now about the future relationship.I still think for UK prime ministers to pick arbitrary dates, and then to make domestic political promises based around them, actually undermines the UK’s negotiating position. It would be in Britain’s interest to have more flexibility rather than a ticking clock.Moving to the other big story from the night, the SNP won 48 of 59 seats in Scotland. How does the debate over Scotland’s future in the United Kingdom play out from here?The SNP has really strengthened its position, more than many expected. This is now set up for a huge constitutional struggle over the future of the United Kingdom.I think there is a key dilemma for Scottish independence supporters, which is that on the one hand Brexit greatly strengthens the political case for independence. The difference between the political preferences in Scotland and the rest of the UK, particularly in England, is a perfect demonstration of that.At the same time, once the UK has left the EU, independence becomes much more difficult technically and economically. There will be many of the same difficulties that there have been in discussing Northern Ireland’s relationship with the Republic of Ireland. There will be a difficult debate over the currency. There are all sorts of challenges to creating a trade or regulatory border between England and Scotland. This is particularly true if there is a harder Brexit outcome, where Britain leaves the EU without a large amount of regulatory alignment.On demands for a second independence referendum, I think in the first instance Boris Johnson will simply refuse to hold one. It’s probably not in his short-term interest to do anything else. Theresa May played it this way in 2017, repeatedly saying ‘now is not the time’.In a similar way I think Johnson will just try to ride the pressure out, to the point where the SNP will need to face the challenges of advocating independence with the UK outside the EU. The next flashpoint will be the elections to the Scottish Parliament in 2021.Ultimately, though, it will become a democratically unsustainable position if Scotland continues to vote for the SNP, and refusing to sanction a second independence referendum might only reinforce that sentiment.Follow Chatham House Twitter for more election coverage Full Article
x In Next Round of EU Negotiations, Britain Faces Familiar Pitfalls By feedproxy.google.com Published On :: Fri, 31 Jan 2020 14:33:27 +0000 31 January 2020 Thomas Raines Director, Europe Programme @TomHRaines Google Scholar Professor Richard G Whitman Associate Fellow, Europe Programme @RGWhitman Google Scholar Despite being free of the constraints and the theatre of a hung parliament, there is a risk that over the coming year the British government repeats too many of the mistakes of the withdrawal negotiations. 2020-01-31-Ldn.jpg The Elizabeth Tower remains under renovation on 31 January 2020. Photo: Getty Images. Whether feared or longed for, Brexit day has arrived. It is positive for all sides that the process is thus far managed and ordered, with debts paid, rights guaranteed and borders still invisible on the island of Ireland. But in a difficult new phase of negotiations, as the UK and EU try to hammer out the terms of their relationship after 2020, Britain is at risk of repeating many of its mistakes from the withdrawal talks.First, the government, through the negotiation timeline, has reduced its own room for manoeuvre. The failure of the initial withdrawal agreement and subsequent turbulent politics have reduced a planned 21-month transition to an 11-month one. Even though half the original negotiation time has been lost, 31 December 2020 remains in place and indeed has been written into UK law as the date the transition arrangement ends. Boris Johnson has followed Theresa May in investing symbolism and significance in an arbitrary date.By promising not to extend negotiations, the UK is boxing itself in, creating domestic political barriers where it may well need flexibility. The familiar face of Michel Barnier, who proved adept in leading the withdrawal negotiations for the EU side, will be back in phase two to tell Britain the clock is ticking. This new timeline is intended to focus minds but more likely it will limit ambitions. Second, this government has continued the pattern of its predecessor in making no effort to manage public expectations about the consequences of Brexit. It is naïve to have followed the last years of British politics and expect an outbreak of sobriety and levelheadedness. The entrenched positions of each side have offered little political space or electoral incentive for realism.During the 2020 transition period, the UK will lose the political rights of EU membership but it will retain the benefits and obligations. Most citizens and business will not be able to tell the difference. But a reckoning is inevitable. There will come a moment when the effects of this slow-motion political revolution – particularly in the hard form envisioned by Boris Johnson – become real, when the trade-offs and compromises, especially for business and the economy, will bite. The public deserve some realism about the price of sovereignty.Third, there is a risk that government remains underprepared. While its headline goals are clear – at least in terms of what it does not want – the UK government will need thorough, realistic and coherent proposals on what it wants in every area of negotiations, and crucially develop a process by which to make political trade-offs between the demands of different sectors and issues. The government must also then prepare for their implementation in every area. This would be a huge challenge even if the final destination was already known, which it is not. Fourth, the continued uncertainty in the process means businesses and civil servants will again be left with little time to adapt to what will face them in January 2021 and must prepare for multiple outcomes.‘Transition’ has always been a misleading term, since it implies clarity about the destination to which the UK–EU relationship will be transitioning. The government’s red lines for that future relationship provide a sketch: outside of the single market and the jurisdiction of the European Court of Justice, with an independent trade policy and free movement ended.But businesses and civil servants are not likely to know until very late in the process if the basis for future trade with the EU will be in the form of a free trade agreement, to be negotiated and implemented by the end of the year, or no trade deal at all. This last outcome is a realistic prospect. Michel Barnier speaks in the European Parliament on 29 January. Photo: Getty Images. During withdrawal negotiations, the extensions were both unlimited in number and required decisions only at the last moment. In this phase, the talks may only be extended once, and that decision must be taken six months from the final deadline. It is difficult to see circumstances in which Boris Johnson agrees to break a political promise and manifesto pledge when he still has six more months to achieve his desired outcome.The UK, it is often noted, is already fully compliant with EU law and this shared starting point is often cited as a reason this negotiation will be simple, since the parties begin in alignment. But this novel negotiation will create new trade barriers in goods and services rather than remove them. Trade deals are often politically difficult since they create winners and losers. The Brexit negotiations, in terms of UK–EU trade at least, will generally create only different levels of losers, on both sides of the Channel.That means difficult politics, challenging negotiations and hard compromises, another reason to expect some ugly politics along the way and accept that failure is a plausible outcome.We do not yet know how Brexit will change Britain in the long term, whether a settled majority will ever come to view it as political folly or liberation, choice or inevitability. If its politically fragile union can withstand the pressures of the next few years, the UK may yet find a new stable position on the EU’s periphery and, after a period of economic adjustment, begin to address the many pressing domestic challenges which have suffered from neglect amid the all-consuming Brexit saga.But whatever happens in this next chapter, the EU can no longer be an excuse for national problems. As the UK takes back control it also returns accountability. In the future, there will be no one else to credit or to blame. Full Article
x Virtual Breakfast: Is a Brexit Delay Possible? By feedproxy.google.com Published On :: Tue, 24 Mar 2020 15:15:01 +0000 Research Event 7 April 2020 - 8:30am to 9:30am Event participants Gavin Barwell, Downing Street Chief of Staff to Prime Minister Theresa May (2017-19)Chair: Thomas Raines, Director, Europe Programme, Chatham House Please note this an online-only event.According to a previously agreed timetable for phase two of Brexit talks, negotiations on the future EU-UK trade relations were scheduled to begin in March. Then a global pandemic hit. Despite the ongoing COVID-19 outbreak, the UK government insists that the Brexit negotiations are on track and there are currently no plans to extend the transition period beyond 2020.However, the original timetable for trade talks was already widely seen as extremely constrained. Can negotiations still be done in time? With the decision on any possible extension to be made by July at the latest, can the two sides make sufficient progress by that point? Or would the ongoing public health crisis make requesting an extension to the transition period more politically viable for the UK government? Finally, if there is no extension, could Britain still leave the EU with no deal?In this webinar, the speaker will discuss how the need to manage other challenges, such as the current COVID-19 outbreak, might affect the government’s approach to the negotiations with the EU. He will also share his insights on what to expect from the second phase of negotiations and on the most important lessons from phase one. Department/project Europe Programme, Britain and Europe: The Post-Referendum Agenda Alina Lyadova Europe Programme Coordinator Email Full Article
x Evolution, expression, and substrate specificities of aldehyde oxidase enzymes in eukaryotes [Enzymology] By feedproxy.google.com Published On :: 2020-04-17T00:06:05-07:00 Aldehyde oxidases (AOXs) are a small group of enzymes belonging to the larger family of molybdo-flavoenzymes, along with the well-characterized xanthine oxidoreductase. The two major types of reactions that are catalyzed by AOXs are the hydroxylation of heterocycles and the oxidation of aldehydes to their corresponding carboxylic acids. Different animal species have different complements of AOX genes. The two extremes are represented in humans and rodents; whereas the human genome contains a single active gene (AOX1), those of rodents, such as mice, are endowed with four genes (Aox1-4), clustering on the same chromosome, each encoding a functionally distinct AOX enzyme. It still remains enigmatic why some species have numerous AOX enzymes, whereas others harbor only one functional enzyme. At present, little is known about the physiological relevance of AOX enzymes in humans and their additional forms in other mammals. These enzymes are expressed in the liver and play an important role in the metabolisms of drugs and other xenobiotics. In this review, we discuss the expression, tissue-specific roles, and substrate specificities of the different mammalian AOX enzymes and highlight insights into their physiological roles. Full Article
x The heme-regulatory motifs of heme oxygenase-2 contribute to the transfer of heme to the catalytic site for degradation [Protein Structure and Folding] By feedproxy.google.com Published On :: 2020-04-17T00:06:05-07:00 Heme-regulatory motifs (HRMs) are present in many proteins that are involved in diverse biological functions. The C-terminal tail region of human heme oxygenase-2 (HO2) contains two HRMs whose cysteine residues form a disulfide bond; when reduced, these cysteines are available to bind Fe3+-heme. Heme binding to the HRMs occurs independently of the HO2 catalytic active site in the core of the protein, where heme binds with high affinity and is degraded to biliverdin. Here, we describe the reversible, protein-mediated transfer of heme between the HRMs and the HO2 core. Using hydrogen-deuterium exchange (HDX)-MS to monitor the dynamics of HO2 with and without Fe3+-heme bound to the HRMs and to the core, we detected conformational changes in the catalytic core only in one state of the catalytic cycle—when Fe3+-heme is bound to the HRMs and the core is in the apo state. These conformational changes were consistent with transfer of heme between binding sites. Indeed, we observed that HRM-bound Fe3+-heme is transferred to the apo-core either upon independent expression of the core and of a construct spanning the HRM-containing tail or after a single turnover of heme at the core. Moreover, we observed transfer of heme from the core to the HRMs and equilibration of heme between the core and HRMs. We therefore propose an Fe3+-heme transfer model in which HRM-bound heme is readily transferred to the catalytic site for degradation to facilitate turnover but can also equilibrate between the sites to maintain heme homeostasis. Full Article
x Reduction of protein phosphatase 2A (PP2A) complexity reveals cellular functions and dephosphorylation motifs of the PP2A/B'{delta} holoenzyme [Enzymology] By feedproxy.google.com Published On :: 2020-04-24T06:08:45-07:00 Protein phosphatase 2A (PP2A) is a large enzyme family responsible for most cellular Ser/Thr dephosphorylation events. PP2A substrate specificity, localization, and regulation by second messengers rely on more than a dozen regulatory subunits (including B/R2, B'/R5, and B″/R3), which form the PP2A heterotrimeric holoenzyme by associating with a dimer comprising scaffolding (A) and catalytic (C) subunits. Because of partial redundancy and high endogenous expression of PP2A holoenzymes, traditional approaches of overexpressing, knocking down, or knocking out PP2A regulatory subunits have yielded only limited insights into their biological roles and substrates. To this end, here we sought to reduce the complexity of cellular PP2A holoenzymes. We used tetracycline-inducible expression of pairs of scaffolding and regulatory subunits with complementary charge-reversal substitutions in their interaction interfaces. For each of the three regulatory subunit families, we engineered A/B charge–swap variants that could bind to one another, but not to endogenous A and B subunits. Because endogenous Aα was targeted by a co-induced shRNA, endogenous B subunits were rapidly degraded, resulting in expression of predominantly a single PP2A heterotrimer composed of the A/B charge–swap pair and the endogenous catalytic subunit. Using B'δ/PPP2R5D, we show that PP2A complexity reduction, but not PP2A overexpression, reveals a role of this holoenzyme in suppression of extracellular signal–regulated kinase signaling and protein kinase A substrate dephosphorylation. When combined with global phosphoproteomics, the PP2A/B'δ reduction approach identified consensus dephosphorylation motifs in its substrates and suggested that residues surrounding the phosphorylation site play roles in PP2A substrate specificity. Full Article
x Processivity of dextransucrases synthesizing very-high-molar-mass dextran is mediated by sugar-binding pockets in domain V [Glycobiology and Extracellular Matrices] By feedproxy.google.com Published On :: 2020-04-24T06:08:45-07:00 The dextransucrase DSR-OK from the Gram-positive bacterium Oenococcus kitaharae DSM17330 produces a dextran of the highest molar mass reported to date (∼109 g/mol). In this study, we selected a recombinant form, DSR-OKΔ1, to identify molecular determinants involved in the sugar polymerization mechanism and that confer its ability to produce a very-high-molar-mass polymer. In domain V of DSR-OK, we identified seven putative sugar-binding pockets characteristic of glycoside hydrolase 70 (GH70) glucansucrases that are known to be involved in glucan binding. We investigated their role in polymer synthesis through several approaches, including monitoring of dextran synthesis, affinity assays, sugar binding pocket deletions, site-directed mutagenesis, and construction of chimeric enzymes. Substitution of only two stacking aromatic residues in two consecutive sugar-binding pockets (variant DSR-OKΔ1-Y1162A-F1228A) induced quasi-complete loss of very-high-molar-mass dextran synthesis, resulting in production of only 10–13 kg/mol polymers. Moreover, the double mutation completely switched the semiprocessive mode of DSR-OKΔ1 toward a distributive one, highlighting the strong influence of these pockets on enzyme processivity. Finally, the position of each pocket relative to the active site also appeared to be important for polymer elongation. We propose that sugar-binding pockets spatially closer to the catalytic domain play a major role in the control of processivity. A deep structural characterization, if possible with large-molar-mass sugar ligands, would allow confirming this hypothesis. Full Article
x The Escherichia coli cellulose synthase subunit G (BcsG) is a Zn2+-dependent phosphoethanolamine transferase [Glycobiology and Extracellular Matrices] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 Bacterial biofilms are cellular communities that produce an adherent matrix. Exopolysaccharides are key structural components of this matrix and are required for the assembly and architecture of biofilms produced by a wide variety of microorganisms. The human bacterial pathogens Escherichia coli and Salmonella enterica produce a biofilm matrix composed primarily of the exopolysaccharide phosphoethanolamine (pEtN) cellulose. Once thought to be composed of only underivatized cellulose, the pEtN modification present in these matrices has been implicated in the overall architecture and integrity of the biofilm. However, an understanding of the mechanism underlying pEtN derivatization of the cellulose exopolysaccharide remains elusive. The bacterial cellulose synthase subunit G (BcsG) is a predicted inner membrane–localized metalloenzyme that has been proposed to catalyze the transfer of the pEtN group from membrane phospholipids to cellulose. Here we present evidence that the C-terminal domain of BcsG from E. coli (EcBcsGΔN) functions as a phosphoethanolamine transferase in vitro with substrate preference for cellulosic materials. Structural characterization of EcBcsGΔN revealed that it belongs to the alkaline phosphatase superfamily, contains a Zn2+ ion at its active center, and is structurally similar to characterized enzymes that confer colistin resistance in Gram-negative bacteria. Informed by our structural studies, we present a functional complementation experiment in E. coli AR3110, indicating that the activity of the BcsG C-terminal domain is essential for integrity of the pellicular biofilm. Furthermore, our results established a similar but distinct active-site architecture and catalytic mechanism shared between BcsG and the colistin resistance enzymes. Full Article
x A Legionella effector kinase is activated by host inositol hexakisphosphate [Enzymology] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 The transfer of a phosphate from ATP to a protein substrate, a modification known as protein phosphorylation, is catalyzed by protein kinases. Protein kinases play a crucial role in virtually every cellular activity. Recent studies of atypical protein kinases have highlighted the structural similarity of the kinase superfamily despite notable differences in primary amino acid sequence. Here, using a bioinformatics screen, we searched for putative protein kinases in the intracellular bacterial pathogen Legionella pneumophila and identified the type 4 secretion system effector Lpg2603 as a remote member of the protein kinase superfamily. Employing an array of biochemical and structural biology approaches, including in vitro kinase assays and isothermal titration calorimetry, we show that Lpg2603 is an active protein kinase with several atypical structural features. Importantly, we found that the eukaryote-specific host signaling molecule inositol hexakisphosphate (IP6) is required for Lpg2603 kinase activity. Crystal structures of Lpg2603 in the apo-form and when bound to IP6 revealed an active-site rearrangement that allows for ATP binding and catalysis. Our results on the structure and activity of Lpg2603 reveal a unique mode of regulation of a protein kinase, provide the first example of a bacterial kinase that requires IP6 for its activation, and may aid future work on the function of this effector during Legionella pathogenesis. Full Article
x Crystallographic and kinetic analyses of the FdsBG subcomplex of the cytosolic formate dehydrogenase FdsABG from Cupriavidus necator [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Formate oxidation to carbon dioxide is a key reaction in one-carbon compound metabolism, and its reverse reaction represents the first step in carbon assimilation in the acetogenic and methanogenic branches of many anaerobic organisms. The molybdenum-containing dehydrogenase FdsABG is a soluble NAD+-dependent formate dehydrogenase and a member of the NADH dehydrogenase superfamily. Here, we present the first structure of the FdsBG subcomplex of the cytosolic FdsABG formate dehydrogenase from the hydrogen-oxidizing bacterium Cupriavidus necator H16 both with and without bound NADH. The structures revealed that the two iron-sulfur clusters, Fe4S4 in FdsB and Fe2S2 in FdsG, are closer to the FMN than they are in other NADH dehydrogenases. Rapid kinetic studies and EPR measurements of rapid freeze-quenched samples of the NADH reduction of FdsBG identified a neutral flavin semiquinone, FMNH•, not previously observed to participate in NADH-mediated reduction of the FdsABG holoenzyme. We found that this semiquinone forms through the transfer of one electron from the fully reduced FMNH−, initially formed via NADH-mediated reduction, to the Fe2S2 cluster. This Fe2S2 cluster is not part of the on-path chain of iron-sulfur clusters connecting the FMN of FdsB with the active-site molybdenum center of FdsA. According to the NADH-bound structure, the nicotinamide ring stacks onto the re-face of the FMN. However, NADH binding significantly reduced the electron density for the isoalloxazine ring of FMN and induced a conformational change in residues of the FMN-binding pocket that display peptide-bond flipping upon NAD+ binding in proper NADH dehydrogenases. Full Article
x Quantification of the affinities of CRISPR-Cas9 nucleases for cognate protospacer adȷacent motif (PAM) sequences [Molecular Biophysics] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 The CRISPR/Cas9 nucleases have been widely applied for genome editing in various organisms. Cas9 nucleases complexed with a guide RNA (Cas9–gRNA) find their targets by scanning and interrogating the genomic DNA for sequences complementary to the gRNA. Recognition of the DNA target sequence requires a short protospacer adjacent motif (PAM) located outside this sequence. Given that the efficiency of target location may depend on the strength of interactions that promote target recognition, here we sought to compare affinities of different Cas9 nucleases for their cognate PAM sequences. To this end, we measured affinities of Cas9 nucleases from Streptococcus pyogenes, Staphylococcus aureus, and Francisella novicida complexed with guide RNAs (gRNAs) (SpCas9–gRNA, SaCas9–gRNA, and FnCas9–gRNA, respectively) and of three engineered SpCas9–gRNA variants with altered PAM specificities for short, PAM-containing DNA probes. We used a “beacon” assay that measures the relative affinities of DNA probes by determining their ability to competitively affect the rate of Cas9–gRNA binding to fluorescently labeled target DNA derivatives called “Cas9 beacons.” We observed significant differences in the affinities for cognate PAM sequences among the studied Cas9 enzymes. The relative affinities of SpCas9–gRNA and its engineered variants for canonical and suboptimal PAMs correlated with previous findings on the efficiency of these PAM sequences in genome editing. These findings suggest that high affinity of a Cas9 nuclease for its cognate PAM promotes higher genome-editing efficiency. Full Article
x Roles of active-site residues in catalysis, substrate binding, cooperativity, and the reaction mechanism of the quinoprotein glycine oxidase [Enzymology] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 The quinoprotein glycine oxidase from the marine bacterium Pseudoalteromonas luteoviolacea (PlGoxA) uses a protein-derived cysteine tryptophylquinone (CTQ) cofactor to catalyze conversion of glycine to glyoxylate and ammonia. This homotetrameric enzyme exhibits strong cooperativity toward glycine binding. It is a good model for studying enzyme kinetics and cooperativity, specifically for being able to separate those aspects of protein function through directed mutagenesis. Variant proteins were generated with mutations in four active-site residues, Phe-316, His-583, Tyr-766, and His-767. Structures for glycine-soaked crystals were obtained for each. Different mutations had differential effects on kcat and K0.5 for catalysis, K0.5 for substrate binding, and the Hill coefficients describing the steady-state kinetics or substrate binding. Phe-316 and Tyr-766 variants retained catalytic activity, albeit with altered kinetics and cooperativity. Substitutions of His-583 revealed that it is essential for glycine binding, and the structure of H583C PlGoxA had no active-site glycine present in glycine-soaked crystals. The structure of H767A PlGoxA revealed a previously undetected reaction intermediate, a carbinolamine product-reduced CTQ adduct, and exhibited only negligible activity. The results of these experiments, as well as those with the native enzyme and previous variants, enabled construction of a detailed mechanism for the reductive half-reaction of glycine oxidation. This proposed mechanism includes three discrete reaction intermediates that are covalently bound to CTQ during the reaction, two of which have now been structurally characterized by X-ray crystallography. Full Article
x Thioredoxin regulates human mercaptopyruvate sulfurtransferase at physiologically-relevant concentrations [Enzymology] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 3-Mercaptopyruvate sulfur transferase (MPST) catalyzes the desulfuration of 3-mercaptopyruvate (3-MP) and transfers sulfane sulfur from an enzyme-bound persulfide intermediate to thiophilic acceptors such as thioredoxin and cysteine. Hydrogen sulfide (H2S), a signaling molecule implicated in many physiological processes, can be released from the persulfide product of the MPST reaction. Two splice variants of MPST, differing by 20 amino acids at the N terminus, give rise to the cytosolic MPST1 and mitochondrial MPST2 isoforms. Here, we characterized the poorly-studied MPST1 variant and demonstrated that substitutions in its Ser–His–Asp triad, proposed to serve a general acid–base role, minimally affect catalytic activity. We estimated the 3-MP concentration in murine liver, kidney, and brain tissues, finding that it ranges from 0.4 μmol·kg−1 in brain to 1.4 μmol·kg−1 in kidney. We also show that N-acetylcysteine, a widely-used antioxidant, is a poor substrate for MPST and is unlikely to function as a thiophilic acceptor. Thioredoxin exhibits substrate inhibition, increasing the KM for 3-MP ∼15-fold compared with other sulfur acceptors. Kinetic simulations at physiologically-relevant substrate concentrations predicted that the proportion of sulfur transfer to thioredoxin increases ∼3.5-fold as its concentration decreases from 10 to 1 μm, whereas the total MPST reaction rate increases ∼7-fold. The simulations also predicted that cysteine is a quantitatively-significant sulfane sulfur acceptor, revealing MPST's potential to generate low-molecular-weight persulfides. We conclude that the MPST1 and MPST2 isoforms are kinetically indistinguishable and that thioredoxin modulates the MPST-catalyzed reaction in a physiologically-relevant concentration range. Full Article
x Civil society perspectives on sexual violence in conflict: patriarchy and war strategy in Colombia By feedproxy.google.com Published On :: Wed, 04 Mar 2020 13:31:21 +0000 4 March 2020 , Volume 96, Number 2 Anne-Kathrin Kreft Read Online In international policy circles, conflict-related sexual violence (CRSV) is commonly viewed as a weapon of war, a framing that researchers have criticized as overly simplistic. Feminist scholars in particular caution that the ‘weapon of war’ framing decontextualizes sexual violence in conflict from the structural factors of gender inequality that underpin its perpetration. In light of these tensions, how do politically relevant local actors perceive the nature and the origins of conflict-related sexual violence? Civil society organizations often actively confront conflict-related sexual violence on the ground. A better understanding of how their perceptions of this violence align or clash with the globally dominant ‘weapon of war’ narratives therefore has important policy implications. Interviews with representatives of Colombian women's organizations and victims' associations reveal that these civil society activists predominantly view conflict-related sexual violence as the result of patriarchal structures. The mobilized women perceive sexual violence as a very gendered violence that exists on a continuum extending through peace, the everyday and war, and which the presence of arms exacerbates. Strategic sexual violence, too, is understood to ultimately have its basis in patriarchal structures. The findings expose a disconnect between the globally dominant ‘weapon of war’ understanding that is decontextualized from structural factors and a local approach to CRSV that establishes clear linkages to societal gender inequality. Full Article
x Predictions and Policymaking: Complex Modelling Beyond COVID-19 By feedproxy.google.com Published On :: Wed, 01 Apr 2020 09:11:23 +0000 1 April 2020 Yasmin Afina Research Assistant, International Security Programme @afinayasmin LinkedIn Calum Inverarity Research Analyst and Coordinator, International Security Programme LinkedIn The COVID-19 pandemic has highlighted the potential of complex systems modelling for policymaking but it is crucial to also understand its limitations. GettyImages-1208425931.jpg A member of the media wearing a protective face mask works in Downing Street where Britain's Prime Minister Boris Johnson is self-isolating in central London, 27 March 2020. Photo by TOLGA AKMEN/AFP via Getty Images. Complex systems models have played a significant role in informing and shaping the public health measures adopted by governments in the context of the COVID-19 pandemic. For instance, modelling carried out by a team at Imperial College London is widely reported to have driven the approach in the UK from a strategy of mitigation to one of suppression.Complex systems modelling will increasingly feed into policymaking by predicting a range of potential correlations, results and outcomes based on a set of parameters, assumptions, data and pre-defined interactions. It is already instrumental in developing risk mitigation and resilience measures to address and prepare for existential crises such as pandemics, prospects of a nuclear war, as well as climate change.The human factorIn the end, model-driven approaches must stand up to the test of real-life data. Modelling for policymaking must take into account a number of caveats and limitations. Models are developed to help answer specific questions, and their predictions will depend on the hypotheses and definitions set by the modellers, which are subject to their individual and collective biases and assumptions. For instance, the models developed by Imperial College came with the caveated assumption that a policy of social distancing for people over 70 will have a 75 per cent compliance rate. This assumption is based on the modellers’ own perceptions of demographics and society, and may not reflect all societal factors that could impact this compliance rate in real life, such as gender, age, ethnicity, genetic diversity, economic stability, as well as access to food, supplies and healthcare. This is why modelling benefits from a cognitively diverse team who bring a wide range of knowledge and understanding to the early creation of a model.The potential of artificial intelligenceMachine learning, or artificial intelligence (AI), has the potential to advance the capacity and accuracy of modelling techniques by identifying new patterns and interactions, and overcoming some of the limitations resulting from human assumptions and bias. Yet, increasing reliance on these techniques raises the issue of explainability. Policymakers need to be fully aware and understand the model, assumptions and input data behind any predictions and must be able to communicate this aspect of modelling in order to uphold democratic accountability and transparency in public decision-making.In addition, models using machine learning techniques require extensive amounts of data, which must also be of high quality and as free from bias as possible to ensure accuracy and address the issues at stake. Although technology may be used in the process (i.e. automated extraction and processing of information with big data), data is ultimately created, collected, aggregated and analysed by and for human users. Datasets will reflect the individual and collective biases and assumptions of those creating, collecting, processing and analysing this data. Algorithmic bias is inevitable, and it is essential that policy- and decision-makers are fully aware of how reliable the systems are, as well as their potential social implications.The age of distrustIncreasing use of emerging technologies for data- and evidence-based policymaking is taking place, paradoxically, in an era of growing mistrust towards expertise and experts, as infamously surmised by Michael Gove. Policymakers and subject-matter experts have faced increased public scrutiny of their findings and the resultant policies that they have been used to justify.This distrust and scepticism within public discourse has only been fuelled by an ever-increasing availability of diffuse sources of information, not all of which are verifiable and robust. This has caused tension between experts, policymakers and public, which has led to conflicts and uncertainty over what data and predictions can be trusted, and to what degree. This dynamic is exacerbated when considering that certain individuals may purposefully misappropriate, or simply misinterpret, data to support their argument or policies. Politicians are presently considered the least trusted professionals by the UK public, highlighting the importance of better and more effective communication between the scientific community, policymakers and the populations affected by policy decisions.Acknowledging limitationsWhile measures can and should be built in to improve the transparency and robustness of scientific models in order to counteract these common criticisms, it is important to acknowledge that there are limitations to the steps that can be taken. This is particularly the case when dealing with predictions of future events, which inherently involve degrees of uncertainty that cannot be fully accounted for by human or machine. As a result, if not carefully considered and communicated, the increased use of complex modelling in policymaking holds the potential to undermine and obfuscate the policymaking process, which may contribute towards significant mistakes being made, increased uncertainty, lack of trust in the models and in the political process and further disaffection of citizens.The potential contribution of complexity modelling to the work of policymakers is undeniable. However, it is imperative to appreciate the inner workings and limitations of these models, such as the biases that underpin their functioning and the uncertainties that they will not be fully capable of accounting for, in spite of their immense power. They must be tested against the data, again and again, as new information becomes available or there is a risk of scientific models becoming embroiled in partisan politicization and potentially weaponized for political purposes. It is therefore important not to consider these models as oracles, but instead as one of many contributions to the process of policymaking. Full Article
x Virtual Roundtable: Evaluating Outcomes in Fragile Contexts: Adapting Research Methods in the Time of COVID-19 By feedproxy.google.com Published On :: Mon, 04 May 2020 08:55:01 +0000 Invitation Only Research Event 5 May 2020 - 12:00pm to 1:00pm Agendapdf | 107.59 KB Event participants Rebecca Wolfe, Lecturer, Harris School for Public Policy and Associate, Pearson Institute for the Study and Resolution of Global Conflicts, University of ChicagoTom Gillhespy, Principal Consultant, ItadShodmon Hojibekov, Chief Executive Officer, Aga Khan Agency for Habitat (Afghanistan)Chair: Champa Patel, Director, Asia-Pacific Programme, Chatham House This virtual roundtable has been co-convened by Chatham House and the Aga Khan Foundation. While conducting research in fragile and conflict-affected contexts has always presented challenges, the outbreak of COVID-19 creates additional challenges including travel restrictions, ethical challenges, and disruptions to usual modes of working. This virtual roundtable will explore how organizations can adapt their research and monitoring and evaluation models in response to the coronavirus pandemic. This event aims to discuss the research methods being used to mitigate the impact of the COVID-19 crisis; the important role of technology; and ways to engage policy and decision-makers during this time. Event attributes Chatham House Rule Department/project Asia-Pacific Programme, Conflict, Peace and Stability, Geopolitics and Governance Lucy Ridout Programme Administrator, Asia-Pacific Programme +44 (0) 207 314 2761 Email Full Article
x Britain is experiencing a little turbulence By feedproxy.google.com Published On :: Thu, 31 Jul 2014 16:04:58 +0000 31 July 2014 , Volume 70, Number 4 A long view of the problems of modern migration Robert Winder is author of ‘Bloody Foreigners' and former literary editor of The Independent and deputy editor of Granta Winder.jpg Some of the first Afro-Caribbean immigrants arrive in East London from Jamaica. Photo: Popperfoto/Getty Full Article
x Abkhazia: Developments in the Domestic and Regional Context By feedproxy.google.com Published On :: Thu, 09 Oct 2014 12:45:01 +0000 Invitation Only Research Event 14 October 2014 - 10:00am to 11:30am Chatham House, London Meeting Summarypdf | 40.6 KB Event participants Viacheslav Chirikba, de facto Minister of Foreign Affairs, Abkhazia Viacheslav Chirikba will offer his perspective on the situation in Abkhazia following the recent presidential elections, and the developments in Abkhazia's relations with other regional players. Attendance at this event is by invitation only. Lubica Pollakova +44 (0)20 7314 2775 Email Full Article
x Challenges to Freedom of Expression By feedproxy.google.com Published On :: Tue, 21 Jun 2016 10:00:01 +0000 Research Event 20 July 2016 - 6:00pm to 7:15pm Chatham House, London Meeting Summarypdf | 107.63 KB Event participants Sherif Elsayed-Ali, Head of Technology and Human Rights, Amnesty InternationalProfessor David Kaye, UN Special Rapporteur on the Promotion and Protection of the Right to Freedom of Opinion and ExpressionChair: Sonya Sceats, Associate Fellow, International Law Programme, Chatham House The digital age has seen an extraordinary transformation in how individuals can exercise their right to freedom of expression. What are the proper limits of state interference in online communication in pursuit of national security and public order? What does this mean for privacy? And away from the digital world, to what extent is free speech being affected by counterterrorism measures and actions to prevent hate crimes? How do all of these challenges affect the space for civil society action? Department/project International Law Programme, Rights, Accountability and Justice, International Law Discussion Group Chanu Peiris Programme Manager, International Law +44 (0)20 7314 3686 Email Full Article
x Syria: Destruction of Civil Society Means Dictatorship, Extremism and Displacement By feedproxy.google.com Published On :: Fri, 07 Oct 2016 08:56:47 +0000 7 October 2016 Rana Marcel Khalaf Former Academy Associate The void in governance in Syria caused by the conflict has enabled a previously oppressed civil society to rise. Now this new society is under threat. Sustained commitment from the international community is required. 2016-10-07-white-helmets-syria2.jpg Syrian civil defence volunteers, known as the White Helmets, search amid the rubble of destroyed buildings following an air strike on the rebel-held neighbourhood of Aleppo, on October 4, 2016. Photo: Getty Images. The void in governance created by the ongoing Syrian conflict has been capitalized upon by warlords, militias and extremist groups to expand and consolidate their power – but has also helped to generate activism, with new leaders born as a reaction to authoritarian governance and conflict limitations.As public social services have been taken over as war tools, local coordination committees, local councils, humanitarian support groups, citizen journalist networks, women’s groups, and more, have mushroomed across all of Syria. But this new civil society continues to be threatened by many challenges.It remains hindered by structural weakness and limited capacity - largely as a result of the legacy of Ba’athist policies, which did not allow civil society to exist in the so-called Damascus Spring, but only under the umbrella of the Government, First Lady Asma al-Assad and business NGOs (GoNGOs, FLNGOs and BoNGOs). Beyond this, civil society was limited to purely charitable and religious causes, known as “moujtamaa ahli”.In addition, Syrian civil society is often a victim of counter-terrorism legislation, with laws and regulations across many countries and institutions prohibiting Syrians from registering an organization and opening bank accounts. This makes it difficult to secure financial support in an environment where funding has already been dwindling due to a “Syria fatigue” among potential donors, and where any money available is mainly directed at large, often international, NGOs.Trust, hope and legitimacyTo reach funds, many organizations have to submit to this “NGOization” process. But even this rarely allows for civil society to foster its own interests through core funding. Civil society in Syria is treated more as a “project” with strict indicators, deals and deadlines, when working under conflict necessitates building relationships of trust with a community over time and often has to cover the direct needs on the ground to gain local legitimacy and increase effectiveness. Trust, hope and legitimacy are not aspects you can report against or cover in a sophisticated proposal.But despite such obstacles, activists and civil society groups continue to volunteer for various causes, ensuring many have not had to seek refuge elsewhere. And their work has included challenging authoritarian and extremist governance.In Aleppo in 2014, it was civil society with the support of a military faction of Jaish Al Mujahideen that helped expel ISIS. Local councils have since been providing services ranging from humanitarian aid and garbage collection to re-establishing order and resolving local conflicts, thus challenging the legitimacy of jihadist institutions.NGOs such as the Civil Defense Forces (known as the White Helmets) continually risk their lives to save others by rescuing people from bombed out buildings. On September 19, when a UN sanctioned aid convoy was attacked in Aleppo – reportedly by Russian aircraft – it was the White Helmets that responded, before then coming under attack themselves.Human rights activists, meanwhile, persist in documenting human rights abuses in the hope that the perpetrators will eventually be held accountable.However, a Syrian civil society tragedy is unfolding as their work is struggling to survive. To give but one example, Kesh Malek, one of the biggest groups running home-based schooling for children in Aleppo, has already had to close some of its schools.Lacking international protection, the fate of these children in relation to arms and radicalization is all the more alarming. Several local councils have also been much weakened, especially vis-à-vis warlords, authoritarian and/or extremists actors.At its best, the current bombing campaign serves to kill any potential alternatives to an authoritarian regime, and only boosts human suffering, radicalization and displacement.If this situation is to be reversed, international actors need to ensure security at the local Syrian level, showing that Syrian security is as important as that of Europe.This means financial security through a deeper and more sustainable capacity building and funding to civil society, and it means protecting civilians and civil society groups though the creation of a safe haven.To comment on this article, please contact Chatham House Feedback Full Article
x Cytochrome P450 and arachidonic acid bioactivation: molecular and functional properties of the arachidonate monooxygenase By feedproxy.google.com Published On :: 2000-02-01 Jorge H. CapdevilaFeb 1, 2000; 41:163-181Reviews Full Article
x Disruption of endoplasmic reticulum structure and integrity in lipotoxic cell death By feedproxy.google.com Published On :: 2006-12-01 Nica M. BorradaileDec 1, 2006; 47:2726-2737Research Articles Full Article
x Marked reduction in bile acid synthesis in cholesterol 7{alpha}-hydroxylase-deficient mice does not lead to diminished tissue cholesterol turnover or to hypercholesterolemia By feedproxy.google.com Published On :: 1998-09-01 Margrit SchwarzSep 1, 1998; 39:1833-1843Articles Full Article
x A spectrophotometric assay for lipid peroxides in serum lipoproteins using a commercially available reagent By feedproxy.google.com Published On :: 1989-04-01 M el-SaadaniApr 1, 1989; 30:627-630Articles Full Article
x Thematic review series: The Pathogenesis of Atherosclerosis The oxidation hypothesis of atherogenesis: the role of oxidized phospholipids and HDL By feedproxy.google.com Published On :: 2004-06-01 Mohamad NavabJun 1, 2004; 45:993-1007Thematic Reviews Full Article
x Normal high density lipoprotein inhibits three steps in the formation of mildly oxidized low density lipoprotein: steps 2 and 3 By feedproxy.google.com Published On :: 2000-09-01 Mohamad NavabSep 1, 2000; 41:1495-1508Articles Full Article
x Gene expression regulation by retinoic acid By feedproxy.google.com Published On :: 2002-11-01 James E. BalmerNov 1, 2002; 43:1773-1808Reviews Full Article
x Normal high density lipoprotein inhibits three steps in the formation of mildly oxidized low density lipoprotein: step 1 By feedproxy.google.com Published On :: 2000-09-01 Mohamad NavabSep 1, 2000; 41:1481-1494Articles Full Article
x Lipid extraction by methyl-tert-butyl ether for high-throughput lipidomics By feedproxy.google.com Published On :: 2008-05-01 Vitali MatyashMay 1, 2008; 49:1137-1146Methods Full Article
x Adipose differentiation-related protein is an ubiquitously expressed lipid storage droplet-associated protein By feedproxy.google.com Published On :: 1997-11-01 DL BrasaemleNov 1, 1997; 38:2249-2263Articles Full Article
x Cell cholesterol efflux: integration of old and new observations provides new insights By feedproxy.google.com Published On :: 1999-05-01 George H. RothblatMay 1, 1999; 40:781-796Reviews Full Article
x Quantitation of atherosclerosis in murine models: correlation between lesions in the aortic origin and in the entire aorta, and differences in the extent of lesions between sexes in LDL receptor-deficient and apolipoprotein E-deficient mice By feedproxy.google.com Published On :: 1995-11-01 RK TangiralaNov 1, 1995; 36:2320-2328Articles Full Article
x Role of the peroxisome proliferator-activated receptor (PPAR) in mediating the effects of fibrates and fatty acids on gene expression By feedproxy.google.com Published On :: 1996-05-01 K SchoonjansMay 1, 1996; 37:907-925Reviews Full Article
x Use of cyclodextrins for manipulating cellular cholesterol content By feedproxy.google.com Published On :: 1997-11-01 AE ChristianNov 1, 1997; 38:2264-2272Articles Full Article
x The amphipathic helix in the exchangeable apolipoproteins: a review of secondary structure and function By feedproxy.google.com Published On :: 1992-02-01 JP SegrestFeb 1, 1992; 33:141-166Reviews Full Article
x Implications of AMLO and Bolsonaro for Mexican and Brazilian Foreign Policy By feedproxy.google.com Published On :: Fri, 14 Feb 2020 10:30:01 +0000 Invitation Only Research Event 26 February 2020 - 12:15pm to 1:15pm Chatham House | 10 St James's Square | London | SW1Y 4LE Event participants Ambassador Andrés Rozental, Senior Adviser, Chatham House; Founding President, Mexican Council on Foreign RelationsDr Elena Lazarou, Associate Fellow, US and the Americas Programme, Chatham HouseChair: Dr Christopher Sabatini, Senior Research Fellow for Latin America, US and the Americas Programme, Chatham House The end of 2018 was a monumental year for Latin America’s two biggest economies. In December 2018, Andrés Manuel López Obrador (AMLO) was inaugurated as Mexico’s 58th president. The following month saw another political shift further south, as Jair Bolsonaro became Brazil’s 38th president. While sitting on opposite ends of the political spectrum, both AMLO and Bolsonaro were considered to be political outsiders and have upended the status quo through their election to office. To what extent does the election of AMLO in Mexico and Bolsonaro in Brazil represent a shift in those countries’ definitions of national interest and foreign policy priorities? How will this affect these states’ policies regarding international commitments and cooperation on issues such as human rights, environment and climate change, migration, and trade? To what extent do possible shifts reflect changing domestic opinions? Will any changes represent a long-term shift in state priorities and policies past these administrations? Department/project US and the Americas Programme, Latin America Initiative US and Americas Programme Email Full Article
x Exploring the Obstacles and Opportunities for Expanded UK-Latin American Trade and Investment By feedproxy.google.com Published On :: Thu, 27 Feb 2020 12:40:01 +0000 Invitation Only Research Event 14 January 2020 - 8:30am to 11:00am Chatham House | 10 St James's Square | London | SW1Y 4LE Trade and investment between the UK and Latin America is woefully underdeveloped. Latin America’s agricultural powerhouses Brazil and Argentina only accounted for a total of 1.6% of the UK’s agricultural market across eight sectors in 2018, all of those areas in which Argentina and Brazil have substantial comparative advantages. Conversely, UK exports to the large Latin American economies remain far below their potential. To cite a few examples, in 2018 in the electrical equipment sector, the UK only exported $95.7 million of those products to Brazil, making the ninth largest economy in the world only the 42nd export market for those goods from the UK; Mexico only imported $91.4 million of UK-made electrical goods, placing it directly behind Brazil as UK’s market for those goods.As we look to the future, any improvement to the relationship will depend on two factors: 1) how the UK leaves the EU and 2) whether Latin American agricultural producers can improve their environmental practices and can meet the production standards established by the EU and likely maintained by a potential post-Brexit Britain.In the first meeting of the working group, Chatham House convened a range of policymakers, practitioners and academics to explore this topic in depth, identify the key issues driving this trend, and begin to consider how improvements might best be made. Subsequent meetings will focus on specific sectors in commerce and investment.We would like to thank BTG Pactual, Cairn Energy plc, Diageo, Equinor, Fresnillo Management Services, HSBC Holdings plc and Wintershall Dea for their generous support of the Latin America Initiative. Event attributes Chatham House Rule Department/project US and the Americas Programme, Latin America Initiative US and Americas Programme Email Full Article
x Civil society perspectives on sexual violence in conflict: patriarchy and war strategy in Colombia By feedproxy.google.com Published On :: Wed, 04 Mar 2020 13:31:21 +0000 4 March 2020 , Volume 96, Number 2 Anne-Kathrin Kreft Read Online In international policy circles, conflict-related sexual violence (CRSV) is commonly viewed as a weapon of war, a framing that researchers have criticized as overly simplistic. Feminist scholars in particular caution that the ‘weapon of war’ framing decontextualizes sexual violence in conflict from the structural factors of gender inequality that underpin its perpetration. In light of these tensions, how do politically relevant local actors perceive the nature and the origins of conflict-related sexual violence? Civil society organizations often actively confront conflict-related sexual violence on the ground. A better understanding of how their perceptions of this violence align or clash with the globally dominant ‘weapon of war’ narratives therefore has important policy implications. Interviews with representatives of Colombian women's organizations and victims' associations reveal that these civil society activists predominantly view conflict-related sexual violence as the result of patriarchal structures. The mobilized women perceive sexual violence as a very gendered violence that exists on a continuum extending through peace, the everyday and war, and which the presence of arms exacerbates. Strategic sexual violence, too, is understood to ultimately have its basis in patriarchal structures. The findings expose a disconnect between the globally dominant ‘weapon of war’ understanding that is decontextualized from structural factors and a local approach to CRSV that establishes clear linkages to societal gender inequality. Full Article
x Coronavirus in Latin America and Mexico: Infection Rates, Immigration and Policy Responses By feedproxy.google.com Published On :: Mon, 23 Mar 2020 17:20:01 +0000 Invitation Only Research Event 25 March 2020 - 4:00pm to 5:00pm Event participants Jude Webber, Mexico and Central America Correspondent, Financial TimesMichael Stott, Latin America Editor, Financial TimesChair: Dr Christopher Sabatini, Senior Research Fellow for Latin America, US and the Americas Programme, Chatham House This event is part of the Inaugural Virtual Roundtable Series on the US, Americas and the State of the World and will take place virtually only. Participants should not come to Chatham House for these events Department/project US and the Americas Programme, Latin America Initiative US and Americas Programme Email Full Article
x S-Palmitoylation of the sodium channel Nav1.6 regulates its activity and neuronal excitability [Cell Biology] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 S-Palmitoylation is a reversible post-translational lipid modification that dynamically regulates protein functions. Voltage-gated sodium channels are subjected to S-palmitoylation and exhibit altered functions in different S-palmitoylation states. Our aim was to investigate whether and how S-palmitoylation regulates Nav1.6 channel function and to identify S-palmitoylation sites that can potentially be pharmacologically targeted. Acyl-biotin exchange assay showed that Nav1.6 is modified by S-palmitoylation in the mouse brain and in a Nav1.6 stable HEK 293 cell line. Using whole-cell voltage clamp, we discovered that enhancing S-palmitoylation with palmitic acid increases Nav1.6 current, whereas blocking S-palmitoylation with 2-bromopalmitate reduces Nav1.6 current and shifts the steady-state inactivation in the hyperpolarizing direction. Three S-palmitoylation sites (Cys1169, Cys1170, and Cys1978) were identified. These sites differentially modulate distinct Nav1.6 properties. Interestingly, Cys1978 is exclusive to Nav1.6 among all Nav isoforms and is evolutionally conserved in Nav1.6 among most species. Cys1978 S-palmitoylation regulates current amplitude uniquely in Nav1.6. Furthermore, we showed that eliminating S-palmitoylation at specific sites alters Nav1.6-mediated excitability in dorsal root ganglion neurons. Therefore, our study reveals S-palmitoylation as a potential isoform-specific mechanism to modulate Nav activity and neuronal excitability in physiological and diseased conditions. Full Article
x {alpha}-Synuclein filaments from transgenic mouse and human synucleinopathy-containing brains are maȷor seed-competent species [Molecular Bases of Disease] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Assembled α-synuclein in nerve cells and glial cells is the defining pathological feature of neurodegenerative diseases called synucleinopathies. Seeds of α-synuclein can induce the assembly of monomeric protein. Here, we used sucrose gradient centrifugation and transiently transfected HEK 293T cells to identify the species of α-synuclein from the brains of homozygous, symptomatic mice transgenic for human mutant A53T α-synuclein (line M83) that seed aggregation. The most potent fractions contained Sarkosyl-insoluble assemblies enriched in filaments. We also analyzed six cases of idiopathic Parkinson's disease (PD), one case of familial PD, and six cases of multiple system atrophy (MSA) for their ability to induce α-synuclein aggregation. The MSA samples were more potent than those of idiopathic PD in seeding aggregation. We found that following sucrose gradient centrifugation, the most seed-competent fractions from PD and MSA brains are those that contain Sarkosyl-insoluble α-synuclein. The fractions differed between PD and MSA, consistent with the presence of distinct conformers of assembled α-synuclein in these different samples. We conclude that α-synuclein filaments are the main driving force for amplification and propagation of pathology in synucleinopathies. Full Article
x Brain manganese and the balance between essential roles and neurotoxicity [Molecular Bases of Disease] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Manganese (Mn) is an essential micronutrient required for the normal development of many organs, including the brain. Although its roles as a cofactor in several enzymes and in maintaining optimal physiology are well-known, the overall biological functions of Mn are rather poorly understood. Alterations in body Mn status are associated with altered neuronal physiology and cognition in humans, and either overexposure or (more rarely) insufficiency can cause neurological dysfunction. The resultant balancing act can be viewed as a hormetic U-shaped relationship for biological Mn status and optimal brain health, with changes in the brain leading to physiological effects throughout the body and vice versa. This review discusses Mn homeostasis, biomarkers, molecular mechanisms of cellular transport, and neuropathological changes associated with disruptions of Mn homeostasis, especially in its excess, and identifies gaps in our understanding of the molecular and biochemical mechanisms underlying Mn homeostasis and neurotoxicity. Full Article
x Virtual Roundtable: Evaluating Outcomes in Fragile Contexts: Adapting Research Methods in the Time of COVID-19 By feedproxy.google.com Published On :: Mon, 04 May 2020 08:55:01 +0000 Invitation Only Research Event 5 May 2020 - 12:00pm to 1:00pm Agendapdf | 107.59 KB Event participants Rebecca Wolfe, Lecturer, Harris School for Public Policy and Associate, Pearson Institute for the Study and Resolution of Global Conflicts, University of ChicagoTom Gillhespy, Principal Consultant, ItadShodmon Hojibekov, Chief Executive Officer, Aga Khan Agency for Habitat (Afghanistan)Chair: Champa Patel, Director, Asia-Pacific Programme, Chatham House This virtual roundtable has been co-convened by Chatham House and the Aga Khan Foundation. While conducting research in fragile and conflict-affected contexts has always presented challenges, the outbreak of COVID-19 creates additional challenges including travel restrictions, ethical challenges, and disruptions to usual modes of working. This virtual roundtable will explore how organizations can adapt their research and monitoring and evaluation models in response to the coronavirus pandemic. This event aims to discuss the research methods being used to mitigate the impact of the COVID-19 crisis; the important role of technology; and ways to engage policy and decision-makers during this time. Event attributes Chatham House Rule Department/project Asia-Pacific Programme, Conflict, Peace and Stability, Geopolitics and Governance Lucy Ridout Programme Administrator, Asia-Pacific Programme +44 (0) 207 314 2761 Email Full Article
x Crimean Reality Check: Four Years of Annexation By feedproxy.google.com Published On :: Wed, 14 Mar 2018 00:00:00 +0000 Full Article
x Building Resistance to Violent Extremism By feedproxy.google.com Published On :: Mon, 23 Apr 2018 00:00:00 +0100 Full Article
x How to Fix Finance by Reinforcing Human Rights By feedproxy.google.com Published On :: Wed, 11 Jul 2018 00:00:00 +0100 Full Article
x Undercurrents: Episode 13 - India's Billionaires, and Sexual Exploitation in the UN By feedproxy.google.com Published On :: Thu, 26 Jul 2018 00:00:00 +0100 Full Article
x Undercurrents: Episode 15 - Brexit Update, and Corruption in the World of the Global Super-Rich By feedproxy.google.com Published On :: Thu, 23 Aug 2018 00:00:00 +0100 Full Article
x A Weapon of War? Sexual Violence in the Syrian Conflict By feedproxy.google.com Published On :: Thu, 06 Sep 2018 00:00:00 +0100 Full Article
x Red Flags: The Outlook for Xi Jinping's China By feedproxy.google.com Published On :: Wed, 12 Sep 2018 00:00:00 +0100 Full Article