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Unusual zwitterionic catalytic site of SARS-CoV-2 main protease revealed by neutron crystallography [Enzymology]

The main protease (3CL Mpro) from SARS–CoV-2, the etiological agent of COVID-19, is an essential enzyme for viral replication. 3CL Mpro possesses an unusual catalytic dyad composed of Cys145 and His41 residues. A critical question in the field has been what the protonation states of the ionizable residues in the substrate-binding active-site cavity are; resolving this point would help understand the catalytic details of the enzyme and inform rational drug development against this pernicious virus. Here, we present the room-temperature neutron structure of 3CL Mpro, which allowed direct determination of hydrogen atom positions and, hence, protonation states in the protease. We observe that the catalytic site natively adopts a zwitterionic reactive form in which Cys145 is in the negatively charged thiolate state and His41 is doubly protonated and positively charged, instead of the neutral unreactive state usually envisaged. The neutron structure also identified the protonation states, and thus electrical charges, of all other amino acid residues and revealed intricate hydrogen-bonding networks in the active-site cavity and at the dimer interface. The fine atomic details present in this structure were made possible by the unique scattering properties of the neutron, which is an ideal probe for locating hydrogen positions and experimentally determining protonation states at near-physiological temperature. Our observations provide critical information for structure-assisted and computational drug design, allowing precise tailoring of inhibitors to the enzyme's electrostatic environment.




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Allosteric activation of proto-oncogene kinase Src by GPCR-beta-arrestin complexes [Enzymology]

G protein–coupled receptors (GPCRs) initiate signaling cascades via G-proteins and beta-arrestins (βarr). βarr-dependent actions begin with recruitment of βarr to the phosphorylated receptor tail and are followed by engagement with the receptor core. βarrs are known to act as adaptor proteins binding receptors and various effectors, but it is unclear whether in addition to the scaffolding role βarrs can allosterically activate their downstream targets. Here we demonstrate the direct allosteric activation of proto-oncogene kinase Src by GPCR–βarr complexes in vitro and establish the conformational basis of the activation. Whereas free βarr1 had no effect on Src activity, βarr1 in complex with M2 muscarinic or β2-adrenergic receptors reconstituted in lipid nanodiscs activate Src by reducing the lag phase in Src autophosphorylation. Interestingly, receptor–βarr1 complexes formed with a βarr1 mutant, in which the finger-loop, required to interact with the receptor core, has been deleted, fully retain the ability to activate Src. Similarly, βarr1 in complex with only a phosphorylated C-terminal tail of the vasopressin 2 receptor activates Src as efficiently as GPCR–βarr complexes. In contrast, βarr1 and chimeric M2 receptor with nonphosphorylated C-terminal tail failed to activate Src. Taken together, these data demonstrate that the phosphorylated GPCR tail interaction with βarr1 is necessary and sufficient to empower it to allosterically activate Src. Our findings may have implications for understanding more broadly the mechanisms of allosteric activation of downstream targets by βarrs.




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Next steps for EU-US cooperation on trade and technology

Next steps for EU-US cooperation on trade and technology 8 December 2022 — 3:00PM TO 4:00PM Anonymous (not verified) 21 November 2022 Online

How can the EU and US increase cooperation on AI, semi-conductors and funding information communication technology services?

On trade and technology policy, the EU and the US are making meaningful progress towards cooperation while at the same time navigating tensions. As senior officials meet on 5 December for the third meeting of the Trade and Technology Council (TTC), both sides have vowed to move towards concrete results. But can the US and EU increase cooperation on artificial intelligence, semiconductors, and funding information communication technology services? 

This event draws on insights from a forthcoming Briefing Paper by Marianne Schneider-Petsinger that explores next steps for US-EU cooperation on trade and technology, which is part of a project supported by the Hanns Seidel Foundation. 




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Why technology does not make easy wars

Why technology does not make easy wars Interview LJefferson 28 November 2022

Stephanie Carvin explains why technology does not overcome the challenges of war.

The invasion of Ukraine has demonstrated that many of the assumptions held about the role of technology in contemporary warfare are flawed. The lesson that technology cannot overcome the challenges of warfare is one that the West has also yet to learn, despite a series of failed interventions since the end of the Cold War.

In a wide-ranging conversation, Isabel Muttreja sat down with Stephanie Carvin to talk about her contribution to the September 2022 issue of International Affairs on ‘how not to war’. They discuss the US’ over-reliance on technology and why ‘easy wars’ become ‘forever wars.’

You argue in your article that the US overly relies on technology in war. When did this start?

I don’t necessarily think the US is exceptional. I think all states have tried in some ways to use technologies. One of the key arguments in the article is that the US is an enlightenment country, and part of the enlightenment is a belief in rationality and science and that you can better things through the application of science.

The idea is that if you have perfect information, you are going to be able to dominate the battlefield, and that’s proven itself to be false.

I think that there is this particular scientific approach or embracing of technology, in the American and in fact larger Western tradition on technology as a way to save lives. There is a strange humanitarian impulse that often underlies this use of technology.

We are seeing a quest to try and get perfect information. The idea is that if you have perfect information, you are going to be able to dominate the battlefield, and that’s proven itself to be false. I’m not even sure you can ever get perfect information.

But it underlines this modern approach, that if you can have all the information that’s out there, crunch it into some kind of algorithm, that you can then target discriminately, proportionately, reduce the level of casualties, and reduce the level of unnecessary damage. And that’s a kind of liberal tradition. You are trying to have your cake and eat it too.

You talk about the US being an ultimately liberal state, but they have been involved in a lot of wars over the last 10–20 years. Is that a contradiction?

I hope it is. But I think it goes back to the enlightenment nature of the United States, which is that the US sees itself as a shining city on a hill that has to protect itself at all costs. Liberals abhor tyranny, and they abhor unnecessary deaths. But I think that the idea is that if you threaten us, we see ourselves as embodying these values, therefore, we have to protect ourselves.

There’s a tendency to not really recognize the kind of insurgencies that we’ve seen in Iraq and Afghanistan, or even Vietnam, as war. We don’t really see that as a kind of armed conflict, even though, arguably, that has been the dominant mode of conflict for some time. They even used to call it ‘military operations other than warfare’. We tend to still think of war as great power competition or as the Second World War.

The West has struggled to culturally understand the way other people fight. And that’s when the laws of war conventions have broken down.

My first book was on prisoners of war in the American tradition. What often determined the treatment of people as prisoners of war was if the United States recognized their form of warfare. There’s a racial element here too that I don’t want to dismiss.

So, for example, the US war in the Philippines at the start of the 20th century: They went in, won a very quick victory over the Spanish and effectively took over the Philippines. And then they had a long insurgency for two years with the native Filipinos who didn’t want US domination. While they gave the Spanish all the prisoner of war rights, they didn’t give them to the Filipinos.

This is because they recognized the form of conflict that the Spanish engaged in, but the Indigenous way of warfare was not recognized. The West has struggled to culturally understand the way other people fight. And that’s when the laws of war conventions have broken down between, say, the United States, the West, and other states.

You talk in your article about the US entering ‘easy wars’ and ending up with ‘forever wars’ – what does this mean?

There’s an allure to this high-tech version of warfare, that it can solve a lot of problems, but it’s an illusion. It is ultimately a bit of a false promise.

The idea that machines are going to replace humans is fundamentally untrue. We are seeing this to a certain extent right now, even in the Russia/Ukraine war. This is very much a battle of machines and soldiers. One of the themes of this issue of International Affairs is hubris. The idea that things that appear to be quick wins often tend to be long-term losses. And that’s exactly what this article is talking about.

‘Forever wars’ is not my favourite term, but it’s this concept that what was promised to be an easy war, a high technology-driven conflict, where you can go in, use some surgically precise weapons, take care of the problem, eliminate your opponent and then extract yourself from a situation, has actually turned into a quagmire.

There’s an allure to this high-tech version of warfare, that it can solve a lot of problems, but it’s an illusion.

The limits of technology become apparent within a few months as well as the fact of the messy business of state-building, or the fact that insurgencies and political movements don’t just disintegrate at the show of some high-tech, sophisticated weaponry. It just tends to mean that these wars do go on for a long time, and you have to eventually extricate yourself, but there’s no clean way to do this. We saw this of course with Afghanistan, and to a large extent Iraq.

We get distracted by the shiny object. We see this promise, we see this vision of a kind of warfare that for some may have great appeal.  There are new super weapons, whether it be cyber information warfare or artificial intelligence. Everyone wants to be ahead of the curve, right?

Are these lessons on technology and ‘easy wars’ applicable to other countries?

I think what we’ve learned about the Russian military is that there’s a lot more at the heart of it. Part of the problem Russia is experiencing is that its capabilities were not what it thought they were. It’s clear that Vladimir Putin was enamoured with a lot of the ideas, like that the Russian military was increasingly high-tech and that they had these hypersonic missiles.

They also had very powerful cyber weapons amongst other things. Putin, too, seems to have been caught up in this idea that he could have had a 72-hour special military operation, which would have taken Kyiv. Clearly, that hasn’t happened. Once again, we see the underestimation of the human factor.




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Targeted Peptide Measurements in Biology and Medicine: Best Practices for Mass Spectrometry-based Assay Development Using a Fit-for-Purpose Approach

Steven A. Carr
Mar 1, 2014; 13:907-917
Technological Innovation and Resources




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A Multidimensional Chromatography Technology for In-depth Phosphoproteome Analysis

Claudio P. Albuquerque
Jul 1, 2008; 7:1389-1396
Research




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Development and validation of a high-throughput whole cell assay to investigate Staphylococcus aureus adhesion to host ligands [Microbiology]

Staphylococcus aureus adhesion to the host's skin and mucosae enables asymptomatic colonization and the establishment of infection. This process is facilitated by cell wall-anchored adhesins that bind to host ligands. Therapeutics targeting this process could provide significant clinical benefits; however, the development of anti-adhesives requires an in-depth knowledge of adhesion-associated factors and an assay amenable to high-throughput applications. Here, we describe the development of a sensitive and robust whole cell assay to enable the large-scale profiling of S. aureus adhesion to host ligands. To validate the assay, and to gain insight into cellular factors contributing to adhesion, we profiled a sequence-defined S. aureus transposon mutant library, identifying mutants with attenuated adhesion to human-derived fibronectin, keratin, and fibrinogen. Our screening approach was validated by the identification of known adhesion-related proteins, such as the housekeeping sortase responsible for covalently linking adhesins to the cell wall. In addition, we also identified genetic loci that could represent undescribed anti-adhesive targets. To compare and contrast the genetic requirements of adhesion to each host ligand, we generated a S. aureus Genetic Adhesion Network, which identified a core gene set involved in adhesion to all three host ligands, and unique genetic signatures. In summary, this assay will enable high-throughput chemical screens to identify anti-adhesives and our findings provide insight into the target space of such an approach.




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Biosynthesis of the sactipeptide Ruminococcin C by the human microbiome: Mechanistic insights into thioether bond formation by radical SAM enzymes [Microbiology]

Despite its major importance in human health, the metabolic potential of the human gut microbiota is still poorly understood. We have recently shown that biosynthesis of Ruminococcin C (RumC), a novel ribosomally synthesized and posttranslationally modified peptide (RiPP) produced by the commensal bacterium Ruminococcus gnavus, requires two radical SAM enzymes (RumMC1 and RumMC2) catalyzing the formation of four Cα-thioether bridges. These bridges, which are essential for RumC's antibiotic properties against human pathogens such as Clostridium perfringens, define two hairpin domains giving this sactipeptide (sulfur-to-α-carbon thioether–containing peptide) an unusual architecture among natural products. We report here the biochemical and spectroscopic characterizations of RumMC2. EPR spectroscopy and mutagenesis data support that RumMC2 is a member of the large family of SPASM domain radical SAM enzymes characterized by the presence of three [4Fe-4S] clusters. We also demonstrate that this enzyme initiates its reaction by Cα H-atom abstraction and is able to catalyze the formation of nonnatural thioether bonds in engineered peptide substrates. Unexpectedly, our data support the formation of a ketoimine rather than an α,β-dehydro-amino acid intermediate during Cα-thioether bridge LC–MS/MS fragmentation. Finally, we explored the roles of the leader peptide and of the RiPP precursor peptide recognition element, present in myriad RiPP-modifying enzymes. Collectively, our data support a more complex role for the peptide recognition element and the core peptide for the installation of posttranslational modifications in RiPPs than previously anticipated and suggest a possible reaction intermediate for thioether bond formation.




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Enhanced enzyme kinetics of reverse transcriptase variants cloned from animals infected with SIVmac239 lacking viral protein X [Microbiology]

HIV Type 1 (HIV-1) and simian immunodeficiency virus (SIV) display differential replication kinetics in macrophages. This is because high expression levels of the active host deoxynucleotide triphosphohydrolase sterile α motif domain and histidine-aspartate domain–containing protein 1 (SAMHD1) deplete intracellular dNTPs, which restrict HIV-1 reverse transcription, and result in a restrictive infection in this myeloid cell type. Some SIVs overcome SAMHD1 restriction using viral protein X (Vpx), a viral accessory protein that induces proteasomal degradation of SAMHD1, increasing cellular dNTP concentrations and enabling efficient proviral DNA synthesis. We previously reported that SAMHD1-noncounteracting lentiviruses may have evolved to harbor RT proteins that efficiently polymerize DNA, even at low dNTP concentrations, to circumvent SAMHD1 restriction. Here we investigated whether RTs from SIVmac239 virus lacking a Vpx protein evolve during in vivo infection to more efficiently synthesize DNA at the low dNTP concentrations found in macrophages. Sequence analysis of RTs cloned from Vpx (+) and Vpx (−) SIVmac239–infected animals revealed that Vpx (−) RTs contained more extensive mutations than Vpx (+) RTs. Although the amino acid substitutions were dispersed indiscriminately across the protein, steady-state and pre-steady-state analysis demonstrated that selected SIVmac239 Vpx (−) RTs are characterized by higher catalytic efficiency and incorporation efficiency values than RTs cloned from SIVmac239 Vpx (+) infections. Overall, this study supports the possibility that the loss of Vpx may generate in vivo SIVmac239 RT variants that can counteract the limited availability of dNTP substrate in macrophages.




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ZBP1 promotes fungi-induced inflammasome activation and pyroptosis, apoptosis, and necroptosis (PANoptosis) [Microbiology]

Candida albicans and Aspergillus fumigatus are dangerous fungal pathogens with high morbidity and mortality, particularly in immunocompromised patients. Innate immune-mediated programmed cell death (pyroptosis, apoptosis, necroptosis) is an integral part of host defense against pathogens. Inflammasomes, which are canonically formed upstream of pyroptosis, have been characterized as key mediators of fungal sensing and drivers of proinflammatory responses. However, the specific cell death pathways and key upstream sensors activated in the context of Candida and Aspergillus infections are unknown. Here, we report that C. albicans and A. fumigatus infection induced inflammatory programmed cell death in the form of pyroptosis, apoptosis, and necroptosis (PANoptosis). Further, we identified the innate immune sensor Z-DNA binding protein 1 (ZBP1) as the apical sensor of fungal infection responsible for activating the inflammasome/pyroptosis, apoptosis, and necroptosis. The Zα2 domain of ZBP1 was required to promote this inflammasome activation and PANoptosis. Overall, our results demonstrate that C. albicans and A. fumigatus induce PANoptosis and that ZBP1 plays a vital role in inflammasome activation and PANoptosis in response to fungal pathogens.




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A drug-resistant {beta}-lactamase variant changes the conformation of its active-site proton shuttle to alter substrate specificity and inhibitor potency [Microbiology]

Lys234 is one of the residues present in class A β-lactamases that is under selective pressure due to antibiotic use. Located adjacent to proton shuttle residue Ser130, it is suggested to play a role in proton transfer during catalysis of the antibiotics. The mechanism underpinning how substitutions in this position modulate inhibitor efficiency and substrate specificity leading to drug resistance is unclear. The K234R substitution identified in several inhibitor-resistant β-lactamase variants is associated with decreased potency of the inhibitor clavulanic acid, which is used in combination with amoxicillin to overcome β-lactamase–mediated antibiotic resistance. Here we show that for CTX-M-14 β-lactamase, whereas Lys234 is required for hydrolysis of cephalosporins such as cefotaxime, either lysine or arginine is sufficient for hydrolysis of ampicillin. Further, by determining the acylation and deacylation rates for cefotaxime hydrolysis, we show that both rates are fast, and neither is rate-limiting. The K234R substitution causes a 1500-fold decrease in the cefotaxime acylation rate but a 5-fold increase in kcat for ampicillin, suggesting that the K234R enzyme is a good penicillinase but a poor cephalosporinase due to slow acylation. Structural results suggest that the slow acylation by the K234R enzyme is due to a conformational change in Ser130, and this change also leads to decreased inhibition potency of clavulanic acid. Because other inhibitor resistance mutations also act through changes at Ser130 and such changes drastically reduce cephalosporin but not penicillin hydrolysis, we suggest that clavulanic acid paired with an oxyimino-cephalosporin rather than penicillin would impede the evolution of resistance.




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Building a Fantasy Army — Recruitment & Logistics

This article is by Toni Šušnjar.

Recruitment and Numbers

The most basic style of recruitment is that of a local militia – rural or urban – where a portion or all of the free men take up arms. Militiamen are usually not highly trained, but they make up for lack of training with motivation: fleeing not only carries social stigma, but is also harshly punished. As such, militias were more effective than what would be expected of “civilians in arms”. Militias almost always depended on relatively cheap and easy to use weapons, though urban militias might have access to more expensive weapons – such as hoplite panoply or crossbows. Tribal militias typically used weapons that were also used for hunting and sport. Peasant levy however was only ever used in a support and harassment role, and often had weapons modified from agricultural implements. Only urban militias could have heavy equipment. A common disadvantage of militia armies is the inability to deploy over long distances and time-frames due to soldiers having a day job; thus, focus on long-term warfare (be it conquest or defence) typically brings about the professionalization of the army. This also means that militias are best used in cases with high political fragmentation – such as city-states.

Continue reading Building a Fantasy Army — Recruitment & Logistics at Mythic Scribes.




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New essay anthology examines the future of the international order

New essay anthology examines the future of the international order News release jon.wallace 7 May 2021

Featuring a new essay by Robin Niblett, Chief Executive of Chatham House, and Leslie Vinjamuri, Director of the US and Americas programme.

Anchoring the World”, a new anthology, features an important new essay by Robin Niblett, Chief Executive of Chatham House, and Leslie Vinjamuri, Director of the US and Americas programme. The essay, “The Liberal Order Begins At Home”, argues powerfully for the revival of a liberal international order.

The essay collection has been produced by the Lloyd George Study Group on World Order, and celebrates the centennial years of Chatham House, Georgetown University’s School of Foreign Service, and the Council on Foreign Relations.

Robin Niblett said:

“In this excellent collection, some authors argue that the United Nations should continue to anchor the international system, while others argue for the creation of a new Concert of Powers.

“Our essay argues that it is both necessary and possible to revive the idea of a liberal international order: necessary (and urgent) because of heightened global competition with China, and possible only if western democracies repair their deep social and economic problems at home.

“We hope this volume carries forward the fortitude and creative spirit that the School of Foreign Service, Chatham House, and the Council on Foreign Relations have brought to the study and practice of international affairs over the past century.”

The Lloyd George Study Group and book were made possible by the generosity of the family of Robert Lloyd George, the great-grandson of British Prime Minister, David Lloyd George.

Anchoring the World is published by Foreign Affairs magazine.




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SNF Dialogues: Social media, social movements and political change

SNF Dialogues: Social media, social movements and political change 6 July 2022 — 2:30PM TO 3:45PM Anonymous (not verified) 15 June 2022 Online

Experts and activists explore how the digital world has changed the nature of social movements and the impact this has on policymaking.

From Extinction Rebellion to Black Lives Matter, social movements are increasingly harnessing social media to project their calls for action. This event, convened in partnership with the SNF Dialogues series, will reflect on the value of social media to social movements and the effects of such digital movements on policymakers. Experts and activists from around the world will explore whether social media is an effective tool for social movements or a distraction, the extent to which digital forms of protest incite social change, and finally if this change has an impact on policy decisions.

The SNF Dialogues, an initiative of the Stavros Niarchos Foundation (SNF), are a series of monthly discussions whose goal is to foster the exchange of ideas, inspire a new way of thinking and acting, and encourage and elevate public discourse across geographic boundaries. The Dialogues discussions are free and open to the public, aiming to bring to light timely questions and developments, share informed reflections and concerns, highlight new data and angles, and present fascinating people, projects and ideas.

The Dialogues are curated and moderated by Anna-Kynthia Bousdoukou and are facilitated by the non-profit journalism organization iMEdD (incubator for Media Education and Development).

The discussion will be conducted in English with simultaneous interpretation into Greek. If you wish to watch the discussion in Greek, tune in here.




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Microtubule affinity-regulating kinase 4 with an Alzheimer's disease-related mutation promotes tau accumulation and exacerbates neurodegeneration [Neurobiology]

Accumulation of the microtubule-associated protein tau is associated with Alzheimer's disease (AD). In AD brain, tau is abnormally phosphorylated at many sites, and phosphorylation at Ser-262 and Ser-356 plays critical roles in tau accumulation and toxicity. Microtubule affinity–regulating kinase 4 (MARK4) phosphorylates tau at those sites, and a double de novo mutation in the linker region of MARK4, ΔG316E317D, is associated with an elevated risk of AD. However, it remains unclear how this mutation affects phosphorylation, aggregation, and accumulation of tau and tau-induced neurodegeneration. Here, we report that MARK4ΔG316E317D increases the abundance of highly phosphorylated, insoluble tau species and exacerbates neurodegeneration via Ser-262/356–dependent and –independent mechanisms. Using transgenic Drosophila expressing human MARK4 (MARK4wt) or a mutant version of MARK4 (MARK4ΔG316E317D), we found that coexpression of MARK4wt and MARK4ΔG316E317D increased total tau levels and enhanced tau-induced neurodegeneration and that MARK4ΔG316E317D had more potent effects than MARK4wt. Interestingly, the in vitro kinase activities of MARK4wt and MARK4ΔG316E317D were similar. When tau phosphorylation at Ser-262 and Ser-356 was blocked by alanine substitutions, MARK4wt did not promote tau accumulation or exacerbate neurodegeneration, whereas coexpression of MARK4ΔG316E317D did. Both MARK4wt and MARK4ΔG316E317D increased the levels of oligomeric forms of tau; however, only MARK4ΔG316E317D further increased the detergent insolubility of tau in vivo. Together, these findings suggest that MARK4ΔG316E317D increases tau levels and exacerbates tau toxicity via a novel gain-of-function mechanism and that modification in this region of MARK4 may affect disease pathogenesis.




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High temperature promotes amyloid {beta}-protein production and {gamma}-secretase complex formation via Hsp90 [Neurobiology]

Alzheimer's disease (AD) is characterized by neuronal loss and accumulation of β-amyloid-protein (Aβ) in the brain parenchyma. Sleep impairment is associated with AD and affects about 25–40% of patients in the mild-to-moderate stages of the disease. Sleep deprivation leads to increased Aβ production; however, its mechanism remains largely unknown. We hypothesized that the increase in core body temperature induced by sleep deprivation may promote Aβ production. Here, we report temperature-dependent regulation of Aβ production. We found that an increase in temperature, from 37 °C to 39 °C, significantly increased Aβ production in amyloid precursor protein-overexpressing cells. We also found that high temperature (39 °C) significantly increased the expression levels of heat shock protein 90 (Hsp90) and the C-terminal fragment of presenilin 1 (PS1-CTF) and promoted γ-secretase complex formation. Interestingly, Hsp90 was associated with the components of the premature γ-secretase complex, anterior pharynx-defective-1 (APH-1), and nicastrin (NCT) but was not associated with PS1-CTF or presenilin enhancer-2. Hsp90 knockdown abolished the increased level of Aβ production and the increased formation of the γ-secretase complex at high temperature in culture. Furthermore, with in vivo experiments, we observed increases in the levels of Hsp90, PS1-CTF, NCT, and the γ-secretase complex in the cortex of mice housed at higher room temperature (30 °C) compared with those housed at standard room temperature (23 °C). Our results suggest that high temperature regulates Aβ production by modulating γ-secretase complex formation through the binding of Hsp90 to NCT/APH-1.




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In conversation with James Manyika, Senior Vice President of Research, Technology and Society at Google

In conversation with James Manyika, Senior Vice President of Research, Technology and Society at Google 12 December 2024 — 11:15AM TO 12:45PM Anonymous (not verified) Chatham House and Online

A conversation on AI’s global, societal and economic impacts.

2024 has been a landmark year for Artificial Intelligence (AI) development, deployment and use, with significant progress in AI-driven science, governance and cooperation. Looking ahead, AI continues to demonstrate economic promise and potential to expand on scientific breakthroughs in areas such as climate and health. This wave of innovation is occurring against a backdrop of geopolitical uncertainty and not all countries are fully able to participate. Heading into 2025, there are urgent questions about how best to maximise shared opportunities when it comes to AI and to advance global cooperation.

James Manyika, Senior Vice President of Research, Technology & Society at Google, will unpack what 2025 will bring for AI in science, economics, global governance and international cooperation. 

Key questions include:

  • What will be AI’s global societal and economic impact in 2025 and beyond? 
  • What are the ways AI could help increase economic growth and economy-wide productivity? What factors must be in place for this to happen?
  • How best can we maximise shared opportunities and advance global cooperation when it comes to AI? Where can public-private partnerships unlock scientific breakthroughs for societal progress, combatting shared global challenges such as climate change and global health issues?  
  • What are the principles of safe, responsible AI, and how should companies remain responsive to their evolution and integrate them into technology design and implementation? 
  • What is the current – and ideal – role of technology companies in emerging mechanisms for global cooperation and national governance on AI?

This event is being held in partnership with Google.

You will receive notice by 13:00 on Wednesday 11 December if you have been successful in securing an in-person place.

The institute occupies a position of respect and trust, and is committed to fostering inclusive dialogue at all events. Event attendees are expected to uphold this by adhering to our code of conduct.




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Chatham House Forum: Are Humans Psychologically Wired to Fight?




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Global Trade Landscape Series 2018: Technological Transitions and the Future of Global Trade




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Dark Commerce: Technology’s Contribution to the Illegal Economy




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Is Technology Destroying Democracy?




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Serbia-Kosovo Dialogue: The Future of Peace and Security in the Western Balkans




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Gender Inequality: Making Technology the Solution, Not the Problem




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Is Technology Re-Engineering Humanity?




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Undercurrents: Bonus Episode - How Technology is Changing International Affairs




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Refugees and Technology: Panel Discussion




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Technology Diplomacy in the Digital Age




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Thematic review series: Adipocyte Biology. The perilipin family of structural lipid droplet proteins: stabilization of lipid droplets and control of lipolysis

Dawn L. Brasaemle
Dec 1, 2007; 48:2547-2559
Thematic Reviews




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Molecular physiology of reverse cholesterol transport

CJ Fielding
Feb 1, 1995; 36:211-228
Reviews




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Chatham House Commission on Democracy and Technology in Europe

Chatham House Commission on Democracy and Technology in Europe News Release sysadmin 25 July 2019

Our project on Democracy and Technology in Europe is now entering its final phase. Now we want your help in shaping the final report.




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Can global technology governance anticipate the future?

Can global technology governance anticipate the future? Expert comment NCapeling 27 April 2021

Trying to govern disruption is perilous as complex technology is increasingly embedded in societies and omnipresent in economic, social, and political activity.

Technology governance is beset by the challenges of how regulation can keep pace with rapid digital transformation, how governments can regulate in a context of deep knowledge asymmetry, and how policymakers can address the transnational nature of technology.

Keeping pace with, much less understanding, the implications of digital platforms and artificial intelligence for societies is increasingly challenging as technology becomes more sophisticated and yet more ubiquitous.

To overcome these obstacles, there is an urgent need to move towards a more anticipatory and inclusive model of technology governance. There are some signs of this in recent proposals by the European Union (EU) and the UK on the regulation of online harms.

Regulation failing to keep up

The speed of the digital revolution, further accelerated by the pandemic, has largely outstripped policymakers’ ability to provide appropriate frameworks to regulate and direct technology transformations.

Governments around the world face a ‘pacing problem’, a phenomenon described by Gary Marchant in 2011 as ‘the growing gap between the pace of science and technology and the lagging responsiveness of legal and ethical oversight that society relies on to govern emerging technologies’.

The speed of the digital revolution, further accelerated by the pandemic, has largely outstripped policymakers’ ability to provide appropriate frameworks to regulate and direct technology transformations

This ever-growing rift, Marchant argues, has been exacerbated by the increasing public appetite for and adoption of new technologies, as well as political inertia. As a result, legislation on emerging technologies risks being ineffective or out-of-date by the time it is implemented.

Effective regulation requires a thorough understanding of both the underlying technology design, processes and business model, and how current or new policy tools can be used to promote principles of good governance.

Artificial intelligence, for example, is penetrating all sectors of society and spanning multiple regulatory regimes without any regard for jurisdictional boundaries. As technology is increasingly developed and applied by the private sector rather than the state, officials often lack the technical expertise to adequately comprehend and act on emerging issues. This increases the risk of superficial regulation which fails to address the underlying structural causes of societal harms.

The significant lack of knowledge from those who aim to regulate compared to those who design, develop and market technology is prevalent in most technology-related domains, including powerful online platforms and providers such as Facebook, Twitter, Google and YouTube.

For example, the ability for governments and researchers to access the algorithms used in the business model of social media companies to promote online content – harmful or otherwise – remains opaque so, to a crucial extent, the regulator is operating in the dark.

The transnational nature of technology also poses additional problems for effective governance. Digital technologies intensify the gathering, harvesting, and transfer of data across borders, challenging administrative boundaries both domestically and internationally.

While there have been some efforts at the international level to coordinate approaches to the regulation of – for example – artificial intelligence (AI) and online content governance, more work is needed to promote global regulatory alignment, including on cross-border data flows and antitrust.

Reactive national legislative approaches are often based on targeted interventions in specific policy areas, and so risk failing to address the scale, complexity, and transnational nature of socio-technological challenges. Greater attention needs to be placed on how regulatory functions and policy tools should evolve to effectively govern technology, requiring a shift from a reactionary and rigid framework to a more anticipatory and adaptive model of governance.

Holistic and systemic versus mechanistic and linear

Some recent proposals for technology governance may offer potential solutions. The EU publication of a series of interlinked regulatory proposals – the Digital Services Act, Digital Markets Act and European Democracy Action Plan – integrates several novel and anticipatory features.

The EU package recognizes that the solutions to online harms such as disinformation, hate speech, and extremism lie in a holistic approach which draws on a range of disciplines, such as international human rights law, competition law, e-commerce, and behavioural science.

By tackling the complexity and unpredictability of technology governance through holistic and systemic approaches rather than mechanistic and linear ones, the UK and EU proposals represent an important pivot from reactive to anticipatory digital governance

It consists of a combination of light touch regulation – such as codes of conduct – and hard law requirements such as transparency obligations. Codes of conduct provide flexibility as to how requirements are achieved by digital platforms, and can be updated and tweaked relatively easily enabling regulations to keep pace as technology evolves.

As with the EU Digital Services Act, the UK’s recent proposals for an online safety bill are innovative in adopting a ‘systems-based’ approach which broadly focuses on the procedures and policies of technology companies rather than the substance of online content.

This means the proposals can be adapted to different types of content, and differentiated according to the size and reach of the technology company concerned. This ‘co-regulatory’ model recognizes the evolving nature of digital ecosystems and the ongoing responsibilities of the companies concerned. The forthcoming UK draft legislation will also be complemented by a ‘Safety by Design’ framework, which is forward-looking in focusing on responsible product design.

By tackling the complexity and unpredictability of technology governance through holistic and systemic approaches rather than mechanistic and linear ones, the UK and EU proposals represent an important pivot from reactive to anticipatory digital governance.

Both sets of proposals were also the result of extensive multistakeholder engagement, including between policy officials and technology actors. This engagement broke down silos within the technical and policy/legal communities and helped bridge the knowledge gap between dominant technology companies and policymakers, facilitating a more agile, inclusive, and pragmatic regulatory approach.

Coherence rather than fragmentation

Anticipatory governance also recognizes the need for new coalitions to promote regulatory coherence rather than fragmentation at the international level. The EU has been pushing for greater transatlantic engagement on regulation of the digital space, and the UK – as chair of the G7 presidency in 2021 – aims to work with democratic allies to forge a coherent response to online harms.

Meanwhile the OECD’s AI Policy Observatory enables member states to share best practice on the regulation of AI, and an increasing number of states such as France, Norway, and the UK are using ‘regulatory sandboxes’ to test and build AI or personal data systems that meet privacy standards.

Not all states currently have the organizational capacity and institutional depth to design and deliver regulatory schemes of this nature, as well as the resource-intensive consultation processes which often accompany them.

So, as an increasing number of states ponder how to ‘futureproof’ their regulation of tomorrow’s technology – whether 6G, quantum computing or biotechnology – there is a need for capacity building in governments both on the theory of anticipatory governance and on how it can be applied in practice to global technology regulation.




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The Arg-293 of Cryptochrome1 is responsible for the allosteric regulation of CLOCK-CRY1 binding in circadian rhythm [Computational Biology]

Mammalian circadian clocks are driven by transcription/translation feedback loops composed of positive transcriptional activators (BMAL1 and CLOCK) and negative repressors (CRYPTOCHROMEs (CRYs) and PERIODs (PERs)). CRYs, in complex with PERs, bind to the BMAL1/CLOCK complex and repress E-box–driven transcription of clock-associated genes. There are two individual CRYs, with CRY1 exhibiting higher affinity to the BMAL1/CLOCK complex than CRY2. It is known that this differential binding is regulated by a dynamic serine-rich loop adjacent to the secondary pocket of both CRYs, but the underlying features controlling loop dynamics are not known. Here we report that allosteric regulation of the serine-rich loop is mediated by Arg-293 of CRY1, identified as a rare CRY1 SNP in the Ensembl and 1000 Genomes databases. The p.Arg293His CRY1 variant caused a shortened circadian period in a Cry1−/−Cry2−/− double knockout mouse embryonic fibroblast cell line. Moreover, the variant displayed reduced repressor activity on BMAL1/CLOCK driven transcription, which is explained by reduced affinity to BMAL1/CLOCK in the absence of PER2 compared with CRY1. Molecular dynamics simulations revealed that the p.Arg293His CRY1 variant altered a communication pathway between Arg-293 and the serine loop by reducing its dynamicity. Collectively, this study provides direct evidence that allosterism in CRY1 is critical for the regulation of circadian rhythm.




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A novel stress-inducible CmtR-ESX3-Zn2+ regulatory pathway essential for survival of Mycobacterium bovis under oxidative stress [Microbiology]

Reactive oxygen species (ROS) are an unavoidable host environmental cue for intracellular pathogens such as Mycobacterium tuberculosis and Mycobacterium bovis; however, the signaling pathway in mycobacteria for sensing and responding to environmental stress remains largely unclear. Here, we characterize a novel CmtR-Zur-ESX3-Zn2+ regulatory pathway in M. bovis that aids mycobacterial survival under oxidative stress. We demonstrate that CmtR functions as a novel redox sensor and that its expression can be significantly induced under H2O2 stress. CmtR can physically interact with the negative regulator Zur and de-represses the expression of the esx-3 operon, which leads to Zn2+ accumulation and promotion of reactive oxygen species detoxication in mycobacterial cells. Zn2+ can also act as an effector molecule of the CmtR regulator, using which the latter can de-repress its own expression for further inducing bacterial antioxidant adaptation. Consistently, CmtR can induce the expression of EsxH, a component of esx-3 operon involved in Zn2+ transportation that has been reported earlier, and inhibit phagosome maturation in macrophages. Lastly, CmtR significantly contributes to bacterial survival in macrophages and in the lungs of infected mice. Our findings reveal the existence of an antioxidant regulatory pathway in mycobacteria and provide novel information on stress-triggered gene regulation and its association with host–pathogen interaction.





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The HRDC domain oppositely modulates the unwinding activity of E. coli RecQ helicase on duplex DNA and G-quadruplex [Enzymology]

RecQ family helicases are highly conserved from bacteria to humans and have essential roles in maintaining genome stability. Mutations in three human RecQ helicases cause severe diseases with the main features of premature aging and cancer predisposition. Most RecQ helicases shared a conserved domain arrangement which comprises a helicase core, an RecQ C-terminal domain, and an auxiliary element helicase and RNaseD C-terminal (HRDC) domain, the functions of which are poorly understood. In this study, we systematically characterized the roles of the HRDC domain in E. coli RecQ in various DNA transactions by single-molecule FRET. We found that RecQ repetitively unwinds the 3'-partial duplex and fork DNA with a moderate processivity and periodically patrols on the ssDNA in the 5'-partial duplex by translocation. The HRDC domain significantly suppresses RecQ activities in the above transactions. In sharp contrast, the HRDC domain is essential for the deep and long-time unfolding of the G4 DNA structure by RecQ. Based on the observations that the HRDC domain dynamically switches between RecA core- and ssDNA-binding modes after RecQ association with DNA, we proposed a model to explain the modulation mechanism of the HRDC domain. Our findings not only provide new insights into the activities of RecQ on different substrates but also highlight the novel functions of the HRDC domain in DNA metabolisms.




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FRET and optical trapping reveal mechanisms of actin activation of the power stroke and phosphate release in myosin V [Enzymology]

Myosins generate force and motion by precisely coordinating their mechanical and chemical cycles, but the nature and timing of this coordination remains controversial. We utilized a FRET approach to examine the kinetics of structural changes in the force-generating lever arm in myosin V. We directly compared the FRET results with single-molecule mechanical events examined by optical trapping. We introduced a mutation (S217A) in the conserved switch I region of the active site to examine how myosin couples structural changes in the actin- and nucleotide-binding regions with force generation. Specifically, S217A enhanced the maximum rate of lever arm priming (recovery stroke) while slowing ATP hydrolysis, demonstrating that it uncouples these two steps. We determined that the mutation dramatically slows both actin-induced rotation of the lever arm (power stroke) and phosphate release (≥10-fold), whereas our simulations suggest that the maximum rate of both steps is unchanged by the mutation. Time-resolved FRET revealed that the structure of the pre– and post–power stroke conformations and mole fractions of these conformations were not altered by the mutation. Optical trapping results demonstrated that S217A does not dramatically alter unitary displacements or slow the working stroke rate constant, consistent with the mutation disrupting an actin-induced conformational change prior to the power stroke. We propose that communication between the actin- and nucleotide-binding regions of myosin assures a proper actin-binding interface and active site have formed before producing a power stroke. Variability in this coupling is likely crucial for mediating motor-based functions such as muscle contraction and intracellular transport.




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Identification of compounds that bind the centriolar protein SAS-6 and inhibit its oligomerization [Computational Biology]

Centrioles are key eukaryotic organelles that are responsible for the formation of cilia and flagella, and for organizing the microtubule network and the mitotic spindle in animals. Centriole assembly requires oligomerization of the essential protein spindle assembly abnormal 6 (SAS-6), which forms a structural scaffold templating the organization of further organelle components. A dimerization interaction between SAS-6 N-terminal “head” domains was previously shown to be essential for protein oligomerization in vitro and for function in centriole assembly. Here, we developed a pharmacophore model allowing us to assemble a library of low-molecular-weight ligands predicted to bind the SAS-6 head domain and inhibit protein oligomerization. We demonstrate using NMR spectroscopy that a ligand from this family binds at the head domain dimerization site of algae, nematode, and human SAS-6 variants, but also that another ligand specifically recognizes human SAS-6. Atomistic molecular dynamics simulations starting from SAS-6 head domain crystallographic structures, including that of the human head domain which we now resolve, suggest that ligand specificity derives from favorable Van der Waals interactions with a hydrophobic cavity at the dimerization site.




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Shared requirements for key residues in the antibiotic resistance enzymes ErmC and ErmE suggest a common mode of RNA recognition [Enzymology]

Erythromycin-resistance methyltransferases are SAM dependent Rossmann fold methyltransferases that convert A2058 of 23S rRNA to m6 2A2058. This modification sterically blocks binding of several classes of antibiotics to 23S rRNA, resulting in a multidrug-resistant phenotype in bacteria expressing the enzyme. ErmC is an erythromycin resistance methyltransferase found in many Gram-positive pathogens, whereas ErmE is found in the soil bacterium that biosynthesizes erythromycin. Whether ErmC and ErmE, which possess only 24% sequence identity, use similar structural elements for rRNA substrate recognition and positioning is not known. To investigate this question, we used structural data from related proteins to guide site-saturation mutagenesis of key residues and characterized selected variants by antibiotic susceptibility testing, single turnover kinetics, and RNA affinity–binding assays. We demonstrate that residues in α4, α5, and the α5-α6 linker are essential for methyltransferase function, including an aromatic residue on α4 that likely forms stacking interactions with the substrate adenosine and basic residues in α5 and the α5-α6 linker that likely mediate conformational rearrangements in the protein and cognate rRNA upon interaction. The functional studies led us to a new structural model for the ErmC or ErmE-rRNA complex.




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The Gonchar–Chudnovskies conjecture and a functional analogue of the Thue–Siegel–Roth theorem

A. I. Aptekarev and M. L. Yattselev
Trans. Moscow Math. Soc. 83 (), 251-268.
Abstract, references and article information




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Flexible Distribution Systems: New Services, Actors and Technologies

Flexible Distribution Systems: New Services, Actors and Technologies 4 September 2018 — 9:00AM TO 10:30AM Anonymous (not verified) 31 July 2018 Chatham House, London

The pace of the energy transition is accelerating. Solar and wind are dramatically falling in cost and displacing fossil fuel generators. Simultaneously, the rapid uptake of electric vehicles and battery storage systems are beginning to send shock-waves through the electricity sector.

As the proportion of distributed energy resources (DERs) connected to the distribution network grows, a significant opportunity is beginning to present itself. What if the concerns of renewable integration and associated costs could be solved by the smart integration of these DERs?

By properly valuing the services DERs can provide, actively managing the distribution system and creating new market places, might a truly renewable electricity system capable of supporting the electrification of heat and transport be possible?

During this roundtable, Andrew Scobie, CEO of Faraday Grid, will provide an overview of the challenges and opportunities faced within the distribution network and explain why the current system is no longer fit for purpose.

This is the inaugural event in the Energy Transitions Roundtable (ETR) series.




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Decarbonizing Heat: A New Frontier for Technologies and Business Models

Decarbonizing Heat: A New Frontier for Technologies and Business Models 27 February 2019 — 8:15AM TO 9:45AM Anonymous (not verified) 3 December 2018 Chatham House | 10 St James's Square | London | SW1Y 4LE

Building space and water heating accounts for over 35 percent of global energy consumption - nearly double that of transport. However, there has been limited progress in decarbonizing the sector to date. International cooperation is required to ensure harmonized policies drag low carbon heating technologies down the cost curve to the extent that low carbon heating is cost competitive and affordable. The initial presentations and discussion focus on:

  • Demand reduction technologies and policies that speed up transformation of the sector.
  • The different challenges for energy efficiency of retrofitting as opposed to new build.
  • The impact of electrification on GHG emissions and the power sector.
  • The comparative role of national and city level initiatives.

The meeting concludes by looking at the challenges and risks in accelerating the transformation of heating and the lessons that can be learned from other sectors.





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Higher Structures in Topology, Geometry, and Physics

Ralph M. Kaufmann, Martin Markl and Alexander A. Voronov, editors. American Mathematical Society, 2024, CONM, volume 802, approx. 330 pp. ISBN: 978-1-4704-7142-2 (print), 978-1-4704-7642-7 (online).

This volume contains the proceedings of the AMS Special Session on Higher Structures in Topology, Geometry, and Physics, held virtually on March...




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The history of model railroading the the Walthers 1970 O Scale Catalog

Tangled Bank posted a photo:




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The history of model railroading the the Walthers 1970 O Scale Catalog

Tangled Bank posted a photo:




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The history of model railroading the the Walthers 1970 O Scale Catalog

Tangled Bank posted a photo:




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Large deviations for perturbed Gaussian processes and logarithmic asymptotic estimates for some exit probabilities

Claudio Macci and Barbara Pacchiarotti
Theor. Probability and Math. Statist. 111 (), 21-43.
Abstract, references and article information





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I'm a Neurologist, and This Is This Is the One 'Healthy' Breakfast I'll Never, Ever Eat




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The Nightly Habit Cardiologists Are Begging You to Never, Ever Do