ad Episode 111 - The Internet of Not Watching Films (IoNWF) Bird Box, Black Mirror and bent iPads By play.acast.com Published On :: Fri, 11 Jan 2019 10:50:14 GMT Happy New Year from the UK Tech Weekly Podcast!We are back this week to discuss what we have been watching (or not watching) over the festive period, including Scott Carey on the meme-marketed sensation of Bird Box and what this says about Netflix's ability to dominate the cultural conversation. Then Tamlin Magee jumps in to talk about the interactive Black Mirror movie Bandersnatch and why it may have been destined to fail.Lastly David Price steps out of the hosting chair to talk about bendy iPads and Apple's strange rhetoric. See acast.com/privacy for privacy and opt-out information. Full Article
ad Dispersed lipid droplets: an intermediate site for lipid transport and metabolism in primary human adipocytes. [Images in Lipid Research] By feedproxy.google.com Published On :: 2020-04-15T13:30:25-07:00 Full Article
ad To Advance Trade and Climate Goals, ‘Global Britain’ Must Link Them By feedproxy.google.com Published On :: Thu, 19 Mar 2020 17:12:54 +0000 19 March 2020 Carolyn Deere Birkbeck Associate Fellow, Global Economy and Finance Programme, and Hoffmann Centre for Sustainable Resource Economy @carolyndeere LinkedIn Google Scholar Dr Emily Jones Associate Professor, Blavatnik School of Government Dr Thomas Hale Associate Professor, Blavatnik School of Government COVID-19 is a sharp reminder of why trade policy matters. As the UK works to forge new trade deals, it must align its trade policy agenda with its climate ambition. 2020-03-19-Boris-Johnson-COP26.jpg Boris Johnson at the launch of the UK-hosted COP26 UN Climate Summit at the Science Museum, London on February 4, 2020. Photo by Jeremy Selwyn - WPA Pool/Getty Images. COVID-19 is a sharp reminder of why trade and climate policy matters. How can governments maintain access to critical goods and services, and ensure global supply chains function in times of crisis?The timing of many trade negotiations is now increasingly uncertain, as are the UK’s plans to host COP26 in November. Policy work continues, however, and the EU has released its draft negotiating text for the new UK-EU trade deal, which includes a sub-chapter specifically devoted to climate. This is a timely reminder both of the pressing need for the UK to integrate its trade and climate policymaking and to use the current crisis-induced breathing space in international negotiations - however limited - to catch up on both strategy and priorities on this critical policy intersection.The UK government has moved fast to reset its external trade relations post-Brexit. In the past month it formally launched bilateral negotiations with the EU and took up a seat at the World Trade Organization (WTO) as an independent member. Until the COVID-19 crisis hit, negotiations were also poised to start with the US.The UK is also in the climate spotlight as host of COP26, the most important international climate negotiation since Paris in 2015, which presents a vital opportunity for the government to show leadership by aligning its trade agenda with its climate and sustainability commitments in bold new ways.Not just an empty aspirationThis would send a signal that ‘Global Britain’ is not just an empty aspiration, but a concrete commitment to lead.Not only is concerted action on the climate crisis a central priority for UK citizens, a growing and increasingly vocal group of UK businesses committed to decarbonization are calling on the government to secure a more transparent and predictable international market place that supports climate action by business.With COP26, the UK has a unique responsibility to push governments to ratchet up ambition in the national contributions to climate action – and to promote coherence between climate ambition and wider economic policymaking, including on trade. If Britain really wants to lead, here are some concrete actions it should take.At the national level, the UK can pioneer new ways to put environmental sustainability – and climate action in particular - at the heart of its trade agenda. Achieving the government’s ambitious Clean Growth Strategy - which seeks to make the UK the global leader in a range of industries including electric cars and offshore wind – should be a central objective of UK trade policy.The UK should re-orient trade policy frameworks to incentivize the shift toward a more circular and net zero global economy. And all elements of UK trade policy could be assessed against environmental objectives - for example, their contribution to phasing out fossil fuels, helping to reverse overexploitation of natural resources, and support for sustainable agriculture and biodiversity.In its bilateral and regional trade negotiations, the UK can and should advance its environment, climate and trade goals in tandem, and implementation of the Paris Agreement must be a core objective of the UK trade strategy.A core issue for the UK is how to ensure that efforts to decarbonise the economy are not undercut by imports from high-carbon producers. Here, a ‘border carbon adjustment (BCA)’ - effectively a tax on the climate pollution of imports - would support UK climate goals. The EU draft negotiating text released yesterday put the issue of BCAs front and centre, making crystal clear that the intersection of climate, environment and trade policy goals will be a central issue for UK-EU trade negotiations.Even with the United States, a trade deal can and should still be seized as a way to incentivize the shift toward a net zero and more circular economy. At the multilateral level, as a new independent WTO member, the UK has an opportunity to help build a forward-looking climate and trade agenda.The UK could help foster dialogue, research and action on a cluster of ‘climate and trade’ issues that warrant more focused attention at the WTO. These include the design of carbon pricing policies at the border that are transparent, fair and support a just transition; proposals for a climate waiver for WTO rules; and identification of ways multilateral trade cooperation could promote a zero carbon and more circular global economy. To help nudge multilateral discussion along, the UK could also ask to join a critical ‘path finder’ effort by six governments, led by New Zealand, to pursue an agreement on climate change, trade and sustainability (ACCTS). This group aims to find ways forward on three central trade and climate issues: removing fossil fuel subsidies, climate-related labelling, and promoting trade in climate-friendly goods and services.At present, the complex challenges at the intersection of climate, trade and development policy are too often used to defer or side-step issues deemed ‘too hard’ or ‘too sensitive’ to tackle. The UK could help here by working to ensure multilateral climate and trade initiatives share adjustment burdens, recognise the historical responsibility of developed countries, and do not unfairly disadvantage developing countries - especially the least developed.Many developing countries are keen to promote climate-friendly exports as part of wider export diversification strategies and want to reap greater returns from greener global value chains. Further, small island states and least-developed countries – many of which are Commonwealth members – that are especially vulnerable to the impacts of climate change and natural disasters, need support to adapt in the face of trade shocks and to build climate-resilient, trade-related infrastructure and export sectors.As an immediate next step, the UK should actively support the growing number of WTO members in favour of a WTO Ministerial Statement on environmental sustainability and trade. It should work with its key trading partners in the Commonwealth and beyond to ensure the agenda is inclusive, supports achievement of the UN Sustainable Development Goals (SDGs) and helps developing countries benefit from a more environmentally sustainable global economy.As the UK prepares to host COP26, negotiates deals with the EU and US, and prepares for its first WTO Ministerial meeting as an independent member, it must show it can lead the way nationally, bilaterally, and multilaterally. And to ensure the government acts, greater engagement from the UK’s business, civil society and research sectors is critical – we need all hands on deck to forge and promote concrete proposals for aligning UK trade policy with the climate ambition our world needs. Full Article
ad COVID-19 and the Iranian Shadows of War By feedproxy.google.com Published On :: Wed, 08 Apr 2020 13:24:47 +0000 8 April 2020 Dr Sanam Vakil Deputy Director and Senior Research Fellow, Middle East and North Africa Programme @SanamVakil Coronavirus has plunged Iran into the country’s biggest crisis since its war with Iraq. More than 30 years later, the lingering effects of the war are shaping Iran’s reaction to the pandemic. 2020-04-08-Iran-COVID-Tehran Spraying disinfectant at Tajrish bazaar in Tehran, Iran, during the coronavirus pandemic in March 2020. Photo by Majid Saeedi/Getty Images. In the face of the COVID-19 pandemic, many global leaders have invoked war analogies – from the Pearl Harbor attack to the collective spirit on display during the Second World War – to highlight past lessons learned or rally their populations.For Iran’s leadership, more recent war analogies hold resonance and help explain the ideological and political conundrum limiting an effective COVID-19 response. While the Islamic Republic has weathered a multitude of challenges, COVID-19 is putting unprecedented strain on Iran’s already fragile, heavily-sanctioned economy and further exposing domestic political fissures amid ongoing international tensions.Iran has been identified as the regional epicentre of the pandemic with a steadily rising number of deaths, including several of the country’s political and military elite. Yet the Iranian government has not evoked the collective memory of the war as an opportunity for national resistance and mobilization.Sluggish and poorly managedThis is unsurprising, because thus far the Iranian government’s response to COVID-19 has been sluggish and poorly managed. After an initial slow response, Iran then attempted to downplay the impact of the virus, covering up the number of cases and deaths and blaming the United States, before implementing a poorly coordinated action plan marred by government infighting.For the Iranian leadership, the Iran-Iraq war has been the single most influential and defining period – it has impacted its political ideology, domestic and security policies and international relations. More than half a million Iranians died, and a paranoid worldview and sense of isolation was cemented among many elite leaders such as Supreme Leader Ali Khamenei.The war created a valiant culture of leadership from Qassem Soleimani to presidents Mahmoud Ahmadinejad and Hashemi Rafsanjani and, over time, has resulted in the development of Iran’s asymmetrical defense capabilities.The war enabled a dark purge of political opponents and the gradual birth of Iran’s reformist faction, all while the ethos of sacrifice and martyrdom was linked to the collective notions of resistance.These would be carried forward in other resistance campaigns both regional and economic. Most defining was Ayatollah Khomeini’s infamous 1988 decision to ‘drink the poisoned chalice’ and end the long war. Three decades later, Iran continues to contend with those outcomes.To acknowledge that the COVID-19 crisis could have equally profound consequences would add further pressure to the Islamic Republic at a time of incomparable vulnerability. Even before this crisis, the Iranian government linked sanctions to economic warfare, making future negotiations conditional on sanctions relief.Iranian hardliners used the opportunity to promote Iran’s subsistence-based resistance economy designed to insulate Iran’s economy from external shocks such as sanctions. While both groups recognize the economic urgency, their contending strategies help explain the muddled government response and the ongoing ideological competition between the political elites.Rouhani has argued that a full lockdown of the Iranian economy is impossible because it is already under significant strain from sanctions - the Iranian economy experienced a 9.5% contraction in 2019 and is expected to worsen in the coming year.That said, through Iran’s New Year holidays the government did take action to slow the spread of the virus, discouraging travel and shutting schools, pilgrimage sites and cancelling Friday prayers. Finally, on 4 April, after receiving permission from Khamenei to do so, Rouhani withdrew $1 billion from Iran’s National Development Fund and is distributing the money through loans and credits to 23 million households.Aid from a number of Iran’s parastatal agencies was also announced. Conversely, in his annual New Year’s speech the supreme leader securitized the crisis by laying blame on the United States for spreading the virus as a form of biological terrorism. Iran’s army chief of staff Major General Bagheri was tasked with building hospitals and the Islamic Revolution Guard Corps given authority to clear the streets.The recent expulsion of Médecins Sans Frontières from Iran highlights the mix of paranoia and resistance culture still on display. US sanctions on Iran have significantly weakened Iran’s economy and limited Tehran’s ability to purchase much needed medical supplies and equipment. Unable to access its foreign reserves due to sanctions, the Rouhani government has applied for a $5 billion loan from the IMF.European countries alongside a number of US members of congress have appealed to the Trump administration to ease sanctions on humanitarian grounds. While Washington continues to pursue its steadfast approach, referring to Iran’s campaign as a ‘sanctions relief scam’, Germany, France, and the UK have offered $5 million in aid and launched INSTEX – a trading mechanism designed to circumvent sanctions to allow non-sanctioned humanitarian trade.The impact of coronavirus on Iranian society remains to be seen. But the impact of sanctions has placed heavy economic and psychological burden on the people. Feeling abandoned by the Iranian state and the United States could produce a mix of contradictory nationalistic and independent impulses.The social contract – already fragile amid protests and government repression – reveals declining trust. Without national mobilization and calls for unity reminiscent of the war period, Iranians have stepped in, highlighting the continued resilience of civil society. Support for the medical establishment has been celebrated throughout the country and on social media. Charities, the private sector - through one initiative known as Campaign Nafas (Breathe) - and diaspora groups have initiated fundraising drives and assistance measures.Iran’s relations with the international community, and specifically the United States, remain an unresolved consequence of the war. The 2015 Iranian nuclear agreement was the closest Tehran and Washington came to resolving decades of tensions, containment and sanctions.COVID-19 has further heightened the trajectory of tensions between Tehran and Washington suggesting that any new deal, while necessary, is not on the cards. Tit-for-tat military exchanges have been on the rise in Iraq and Yemen while American and Iranian leaders issue threats and warnings of potential escalation.Abdullah Nasseri, an advisor to Iran’s reformists, recently stated that in order to manage the coronavirus crisis, the Iranian government needed to make a decision akin to the 1988 United Nations resolution 598 that ended war hostilities. Ayatollah Khomeini famously commented on that ceasefire, stating: ‘Happy are those who have departed through martyrdom. Unhappy am I that I still survive.… Taking this decision is more deadly than drinking from a poisoned chalice. I submitted myself to Allah's will and took this drink for His satisfaction’. While a similar compromise today might appear deadly to the political establishment, it is clear that a paradigm shift away from the shadows of Iran’s last war is urgently needed to manage the challenges stemming from COVID-19. Full Article
ad Nigeria’s Political Leaders Need to Win Trust to Tackle COVID-19 By feedproxy.google.com Published On :: Thu, 23 Apr 2020 16:00:22 +0000 23 April 2020 Elizabeth Donnelly Deputy Director, Africa Programme @LizzyDonn Idayat Hassan Director, Centre for Democracy and Development COVID-19 will require Nigeria's government to rely on already stretched communities and informal institutions. But there is a yawning gap in trust and accountability between citizens and the state in Nigeria – the crisis will force the state to attempt to bridge this divide. 2020-04-23-Nigeria-News-Coronavirus News stand in Lagos, Nigeria on April 12, 2020. Photo by PIUS UTOMI EKPEI/AFP via Getty Images. Nigeria is better placed than many to respond to the arrival of the coronavirus disease. In 2014, it successfully contained a deadly Ebola virus outbreak and the country’s current score on the Epidemic Preparedness Index (38.9 per cent) is higher than the African and global averages.But the outbreak is compounding Nigeria’s numerous pre-existing crises. It was already grappling with a Lassa fever outbreak that has claimed more than one hundred lives in 2020, the aftermath of recession, and conflict and insecurity within its borders.Effective leadership to build confidence will be vital. However, President Muhammadu Buhari has made few appearances, delivering his first speech on Nigeria’s response more than one month after the country’s first recorded case. And the indefinite suspension of meetings of the Federal Executive Council has raised questions on the efficacy of the response.Extended lockdown imposedThe recent loss of President Buhari’s steadfast chief of staff Abba Kyari as a result of contracting COVID-19 is a further significant setback for the presidency. But the administration has established a presidential task force to develop a national strategy and an extended lockdown has been imposed on the most affected states – Lagos, Ogun and the Federal Capital Territory of Abuja. The country has also closed national borders and is expanding testing capacity to 1,500 per day.However, when Nigeria’s first case was recorded on February 27 it was state governments that initially took action – shutting schools, closing state borders and imposing lockdowns. Going forwards, the 36 state governments will have a key role to play although their governance capacity and commitment varies widely.The federal government has released $2.7 million to support the Nigeria Centre for Disease Control (NCDC), and promised an additional $18 million – but this falls well short of the estimated $330 million needed to tackle the coronavirus disease in Nigeria. The government is looking to its private sector to help make up the difference. The country’s finances are under severe pressure with Nigerian crude oil – the main source of government revenue and foreign exchange reserves – selling for as low as $12 or $13 a barrel (with production costs of around $22 per barrel), and a debt servicing to revenue ratio of more than 50 per cent even before the oil price crash.Facing its second recession in four years, with -3.4 per cent GDP growth forecast by the IMF, the country has little economic resilience. Nigeria will not be able to sustain restrictions on its 81.15 million-strong workforce, 83.2 per cent of which operate in the informal sector. One area at particular risk is food security, as the pandemic is disrupting farming, supply chains and trade. By building on past benefit programmes, the federal government is providing cash and distributing food to vulnerable households, but this important effort is being hampered by poor communication, inefficiencies and a lack of transparency – longstanding challenges in many aspects of public service delivery in Nigeria.In the absence of a reliable social safety net, Nigerians trust and rely on their families, communities and the informal economy to see them through difficult times. It is these informal mechanisms that lend Nigeria its oft-referenced resilience, which has enabled society to function and continue while a largely disconnected political class has focused on self-enrichment.It is through these traditional channels that the government will need to deliver information, support, testing and treatment. But without high levels of trust, the administration may find it difficult to do so. Many Nigerians initially considered the pandemic a hoax, some describing it as a ‘rich man’s disease’, while others see it as another conspiracy by politicians to loot the treasury.Lockdown measures have also heightened tensions across the country. Some citizens are rebelling and in one instance burned down a police station in response to the closure of mosques in Katsina state. Marking a further breakdown in the relationship between the population and its leaders, the Nigerian National Human Rights Commission (NHRC) recently reported security services enforcing the lockdown have extrajudicially killed 18 people, while, so far, COVID-19 has killed 25 people in Nigeria.Mitigating the spread and worst consequences of the virus will depend on the state rebuilding trust with its citizens through effective communication and action. It is particularly important that the community mechanisms of support are protected as they come under growing pressure as communities become increasingly affected by the virus.The stark choice facing most Nigerians – between risking starvation and risking contagion – means a sustained lockdown is not a tenable option. People will choose to go to work. This will especially be the case as people grow weary of measures imposed upon them by a state that the vast majority of the population believe does not serve or care for them.Having largely ignored the needs of Nigeria’s citizens for decades, the political class face an uphill battle in building trust with the population. Earning this trust is not only crucial for the struggle against COVID-19 but also for Nigeria’s longer-term progress and system of political governance. Full Article
ad COVID-19 in South Africa: Leadership, Resilience and Inequality By feedproxy.google.com Published On :: Thu, 07 May 2020 14:50:58 +0000 7 May 2020 Christopher Vandome Research Fellow, Africa Programme LinkedIn In a world looking for leadership, South Africa’s president Cyril Ramaphosa has been remarkable. One year after he carried the time-worn ANC through a national election, South Africans are crying out for more. 2020-05-07-Ramaphosa-COVID-South-Africa Cyril Ramaphosa at NASREC Expo Centre in Johannesburg where facilities are in place to treat coronavirus patients. Photo by JEROME DELAY/POOL/AFP via Getty Images. In the COVID-19 crisis so far, Cyril Ramaphosa has been widely praised for displaying the decisive leadership so many hoped for when they cast their ballot for him in May 2019. Buttressed by others such as health minister Dr Zweli Mkhize, and on a simple objective to prevent transmission, South Africa has been a lesson to the world. Act fast. Act hard.Former president Thabo Mbeki’s disastrous response to the HIV crisis cast a long shadow over his legacy, and Ramaphosa has taken note. South Africa has had one of the tightest lockdowns in the world. No exercise. No cigarettes. No alcohol.The lockdown was imposed when the country had only around 1,000 recorded cases and just two deaths. As a result, transmission from returning travellers has not yet led to an exponential infection rate within the community. The government’s swift reaction has bought much needed time with the peak now seemingly delayed to September or October.Continental and national leadershipRamaphosa has also emerged as a key focal point for Africa-wide responses. As current chair of the African Union (AU) he leads the continental engagement with the World Health Organization (WHO), and the various international finance institutions, while South African officials are working with the AU and the United Nations Economic Commission for Africa (UNECA) on a push for African debt restructuring.He has also been active in trouble shooting to unlock external assistance to the continent, including from China and Russia. Appointing special envoys is typical of his boardroom-honed leadership style.International and regional partnerships are vital for resilience and the arrival of 217 Cuban doctors to South Africa is strongly reminiscent of the liberationist solidarity of the Cold War era. And regional economies remain dependent on South Africa to protect their own vulnerable citizens. Following the 2008 financial crisis, it was South Africa’s regional trading relationships that remained robust, while trade with its main global partners in China and the US dropped.Despite the plaudits, Ramaphosa remains vulnerable to challenge at home, notably around his failure to stimulate South Africa’s moribund economy. On the eve of lockdown, Moody’s joined its peers Standard and Poor’s and Fitch in giving South Africa a below investment grade credit rating. The move was a long time coming. Long mooted economic reforms were slow to materialise, and South Africa had fallen into recession.Ramaphosa depends on a small core of close advisors and allies, initially united in apparent opposition to the kleptocratic rule of President Jacob Zuma and the deep patronage networks he created within both the party and the state. But this allegiance is being tested by economic reality. Support within the party was already drifting prior to the crisis.Disagreements are not just technocratic – there are big ideological questions in play around the role of the state in the economy, the level of intervention, and its affordability, with key government figures sceptical of rapid market reforms. Energy minister and former union stalwart Gwede Mantashe is wary of job losses, and minister of public enterprises Pravin Gordhan protective of state-owned enterprises (SOEs). Before coronavirus hit, Ramaphosa seemed content to allow these policy disputes to play themselves out with little decisive intervention.Slow progress on reform, against worsening economic performance, left Ramaphosa and his allies exposed. In January the president missed the UK’s African Investment Summit in order to assert control over a party meeting at which it was expected his detractors would seek to remove Gordhan.COVID-19 has sharpened thinkingAs the independently assertive - and eminently quotable - pro-market reformist finance minister Tito Mboweni stated, ‘you can’t eat ideology’. Accelerated reform and restructuring is required if the government turns to the International Monetary Fund (IMF) for assistance.For the first time, Gordhan has been forced to deny a bailout to beleaguered state airline South African Airways (SAA), and the government’s lockdown bailout of R300 billion has been applauded by business. Much like the fiscal stimulus and recovery plan of 2018, it relies on smart spending, targeting sectors with high multiplier effects. It also includes significant reserve bank loans.But it has been criticised for not doing enough to help the most vulnerable. There is considerable fear of what could happen when the virus takes hold in South Africa’s townships and informal settlements where social distancing is almost impossible, basic toilet facilities are shared, and HIV and TB rates high.There are mounting concerns of the humanitarian cost of a prolonged lockdown, and the government has been faster than others in implementing a tiered lockdown system, trying to get people back to work and keep the economy afloat.South Africa has been criticized by the UN for the use of lethal force by security forces in enforcing lockdown and, in a society plagued by corruption, there are fears legislation to stop the spread of false information could be used to restrict legitimate reporting on the virus response or other issues.COVID-19 shines a spotlight on societies’ fault-lines worldwide. South Africa is often touted as having one of the highest levels of inequality in the world but, in a globalized economy, these divisions are international as much as they are local.Resilience comes from within, but also depends on regional and global trading and financial systems. South Africans and international partners have long recognised Ramaphosa’s leadership qualities as an impressive voice for the global south.But he must also be an advocate for South Africa’s poor. This crisis could accelerate implementation of his landmark pro-poor National Health Insurance and Universal Health Care programmes. Or the hit of COVID-19 on top of South Africa’s existing economic woes could see them derailed entirely. Ramaphosa must push through economic reforms at the same time as managing COVID-19 and rebuilding trust in his government. Full Article
ad Immediate adaptation analysis implicates BCL6 as an EGFR-TKI combination therapy target in NSCLC [Research] By feedproxy.google.com Published On :: 2020-03-31T09:35:18-07:00 Drug resistance is a major obstacle to curative cancer therapies, and increased understanding of the molecular events contributing to resistance would enable better prediction of therapy response, as well as contribute to new targets for combination therapy. Here we have analyzed the early molecular response to epidermal growth factor receptor (EGFR) inhibition using RNA sequencing data covering 13 486 genes and mass spectrometry data covering 10 138 proteins. This analysis revealed a massive response to EGFR inhibition already within the first 24 hours, including significant regulation of hundreds of genes known to control downstream signaling, such as transcription factors, kinases, phosphatases and ubiquitin E3-ligases. Importantly, this response included upregulation of key genes in multiple oncogenic signaling pathways that promote proliferation and survival, such as ERBB3, FGFR2, JAK3 and BCL6, indicating an early adaptive response to EGFR inhibition. Using a library of more than 500 approved and experimental compounds in a combination therapy screen, we could show that several kinase inhibitors with targets including JAK3 and FGFR2 increased the response to EGFR inhibitors. Further, we investigated the functional impact of BCL6 upregulation in response to EGFR inhibition using siRNA-based silencing of BCL6. Proteomics profiling revealed that BCL6 inhibited transcription of multiple target genes including p53, resulting in reduced apoptosis which implicates BCL6 upregulation as a new EGFR inhibitor treatment escape mechanism. Finally, we demonstrate that combined treatment targeting both EGFR and BCL6 act synergistically in killing lung cancer cells. In conclusion, or data indicates that multiple different adaptive mechanisms may act in concert to blunt the cellular impact of EGFR inhibition, and we suggest BCL6 as a potential target for EGFR inhibitor-based combination therapy. Full Article
ad Proteome and phosphoproteome analysis of brown adipocytes reveals that RICTOR loss dampens global insulin/AKT signaling [Research] By feedproxy.google.com Published On :: 2020-04-06T05:35:14-07:00 Stimulating brown adipose tissue (BAT) activity represents a promising therapy for overcoming metabolic diseases. mTORC2 is important for regulating BAT metabolism, but its downstream targets have not been fully characterized. In this study, we apply proteomics and phosphoproteomics to investigate the downstream effectors of mTORC2 in brown adipocytes. We compare wild-type controls to isogenic cells with an induced knockout of the mTORC2 subunit RICTOR (Rictor-iKO) by stimulating each with insulin for a 30-minute time course. In Rictor-iKO cells, we identify decreases to the abundance of glycolytic and de novo lipogenesis enzymes, and increases to mitochondrial proteins as well as a set of proteins known to increase upon interferon stimulation. We also observe significant differences to basal phosphorylation due to chronic RICTOR loss including decreased phosphorylation of the lipid droplet protein perilipin-1 in Rictor-iKO cells, suggesting that RICTOR could be involved with regulating basal lipolysis or droplet dynamics. Finally, we observe mild dampening of acute insulin signaling response in Rictor-iKO cells, and a subset of AKT substrates exhibiting statistically significant dependence on RICTOR. Full Article
ad Characterization of signaling pathways associated with pancreatic {beta}-cell adaptive flexibility in compensation of obesity-linked diabetes in db/db mice [Research] By feedproxy.google.com Published On :: 2020-04-07T14:34:38-07:00 The onset of obesity-linked type 2 diabetes (T2D) is marked by an eventual failure in pancreatic β-cell function and mass that is no longer able to compensate for the inherent insulin resistance and increased metabolic load intrinsic to obesity. However, in a commonly used model of T2D, the db/db mouse, β-cells have an inbuilt adaptive flexibility enabling them to effectively adjust insulin production rates relative to the metabolic demand. Pancreatic β-cells from these animals have markedly reduced intracellular insulin stores, yet high rates of (pro)insulin secretion, together with a substantial increase in proinsulin biosynthesis highlighted by expanded rough endoplasmic reticulum and Golgi apparatus. However, when the metabolic overload and/or hyperglycemia is normalized, β-cells from db/db mice quickly restore their insulin stores and normalize secretory function. This demonstrates the β-cell’s adaptive flexibility and indicates that therapeutic approaches applied to encourage β-cell rest are capable of restoring endogenous β-cell function. However, mechanisms that regulate β-cell adaptive flexibility are essentially unknown. To gain deeper mechanistic insight into the molecular events underlying β-cell adaptive flexibility in db/db β-cells, we conducted a combined proteomic and post-translational modification specific proteomic (PTMomics) approach on islets from db/db mice and wild-type controls (WT) with or without prior exposure to normal glucose levels. We identified differential modifications of proteins involved in redox homeostasis, protein refolding, K48-linked deubiquitination, mRNA/protein export, focal adhesion, ERK1/2 signaling, and renin-angiotensin-aldosterone signaling, as well as sialyltransferase activity, associated with β-cell adaptive flexibility. These proteins are all related to proinsulin biosynthesis and processing, maturation of insulin secretory granules, and vesicular trafficking—core pathways involved in the adaptation of insulin production to meet metabolic demand. Collectively, this study outlines a novel and comprehensive global PTMome signaling map that highlights important molecular mechanisms related to the adaptive flexibility of β-cell function, providing improved insight into disease pathogenesis of T2D. Full Article
ad International Arms Trade Treaty: Gun Control By feedproxy.google.com Published On :: Wed, 15 Apr 2020 11:39:18 +0000 1 October 2008 , Number 11 Nuclear, biological or chemical weapons and acts of terror may make the headlines, but it is conventional arms that take the lives in large numbers; maybe around a thousand a day. This month, a United Nations committee will try to find a way to limit the arms trade with a new treaty. For those facing the barrel of a gun, it cannot come a moment too soon. Paul Cornish Head, International Security Programme, Chatham House Field.jpg Full Article
ad Chemical, Biological, Radiological and Nuclear Terrorism: Tomorrow's Threat By feedproxy.google.com Published On :: Mon, 27 Apr 2020 13:23:42 +0000 1 March 2007 , Number 11 In early November, the retiring head of Britain’s Security Service MI5, Dame Eliza Manningham-Buller, warned that the danger of a terror attack was ‘serious’ and ‘growing’, with as many as thirty plots underway. Traditional terrorism of the sort practised by the Irish Republican Army has given way to the possibility, if not the expectation, that groups such as Al Qaeda might make use of chemical, biological, radiological and nuclear weapons and materials in an attack in Britain. So what are the dangers? GettyImages-200457787-001 copy.jpg Syrian Special Forces in gas masks, Saudi Arabia 1990 Full Article
ad Could Zelenskyy’s Strategy for Donbas Lead Ukraine Into a Kremlin Trap? By feedproxy.google.com Published On :: Fri, 14 Feb 2020 09:54:05 +0000 14 February 2020 Kataryna Wolczuk Associate Fellow, Russia and Eurasia Programme Google Scholar Hanna Shelest Member of the Board, Foreign Policy Council 'Ukrainian Prism' In pursuit of peace in the war-torn region, the Ukrainian president’s short-term, tactical approach is vulnerable in the face of Russia’s long-term strategy. 2020-02-14-Zelenskyy.jpg Volodymyr Zelenskyy attends a ceremony welcoming Ukrainians who were freed by pro-Russian rebels during a prisoner exchange. Photo: Getty Images. One of the key messages at the heart of Volodymyr Zelenskyy’s presidential campaign in 2019 was a very simple one: peace in Donbas, the war-torn region of Ukraine where Russian-supported separatists continue to fight a war against the Kyiv government. Zelenskyy’s message was based on the assumption that if a ceasefire could be respected, and all Ukrainian prisoners-of-war could return home, then peace would have been achieved.Nine months after Zelenskyy’s inauguration and two months after his first Normandy Four summit (which brings together Germany and France with Ukraine and Russia to discuss Donbas), it appears more likely that this approach will lead Ukraine into a Russian trap.Zelenskyy’s very immediate objectives and the tactics used to achieve them contrast with those of the previous president, Petro Poroshenko. Zelenskyy has pointedly avoided naming Russia as an aggressor and has focused on humanitarian issues and seeking compromise wherever possible, including in legal cases that Russia has already lost in international courts.In contrast, President Poroshenko prioritised the security agenda as a precondition for any political settlement, encapsulated in the notion of ‘no elections without security guarantees’. This focused on regaining control of the border and the demilitarization of the separatist-controlled territories. At the same time, Poroshenko sought remedial action for Russian aggression through international courts. Kyiv is testing the Kremlin’s real intentions with a series of small steps without clearly communicating its overarching objectives. This has triggered considerable social disquiet, manifested by demonstrations in Kyiv and other cities as part of the ’No capitulation’ campaign. This wave of criticism forced Zelenskyy’s team to name certain red lines, which he promised he would not cross (‘we don’t trade territories and people’) in pursuit of conflict resolution.Other key issues, such as Ukraine’s relations with the EU, future NATO membership, language issues and any possible ‘special status’ for Donbas, have been left undefined.Two months since the Normandy summit, the number of casualties has not declined. It is increasingly difficult for Zelenskyy to argue that disengagement by Ukraine’s army from the contact line in three locations, which was a precondition for the December Normandy Four meeting, is a way to achieve peace.The separatists continue to significantly impede the OSCE’s special monitoring mission, a full ceasefire is not being observed and there are numerous reports of heavy weapons movements closer to the contact line in the areas outside Kyiv’s control. These issues are particularly problematic as control over the border with Russia is essential for the demilitarization of the ‘people’s republics’, which is a prerequisite for the safe reintegration of these areas.Conducting local elections in autumn 2020 is a top priority for the new team, but it is clear that even if Ukraine regains control of its border, the presence of Russian military personnel and weaponry in Donbas threatens the prospect of free and fair elections (which themselves raise the further issue of how to ensure the integrity of the votes).Russia’s strategySo despite Zelenskyy’s pacifist rhetoric, hopes and ambitions, his plans are far from being realized or, in fact, realizable. This is because these plans are at odds with Russia’s strategic objective, which is for Donbas to be conferred a status whereby it is de jure within Ukraine but de facto under Russian control and influence.Zelenskyy’s media-friendly appearance in Paris in December 2019 could not mask the fact that the Normandy Four talks exposed the weakness of Ukraine’s position and the growing influence of Russia’s approach, particularly in the context of a disengaged UK and US, a Germany increasingly tired of this conflict, and a French president who is looking to accommodate Russian preferences.Indeed, Vladimir Putin was able to exploit the opportunity to apply his favoured formula for conducting foreign policy: highly personalized informal interactions, which seek specific political concessions from a cornered partner and which are short on transparent, stable and law-based solutions. The Paris meeting of the Normandy Four in December 2019 clearly demonstrated that simply sitting down and talking to Putin is not a magic pill to end the conflict, an idea frequently expressed by Zelenskyy.In 2020, the strongest clue as to what Putin’s plans for Ukraine might be is the appointment of Dmitry Kozak as the main curator of the ‘Ukraine file’ (meaning Donbas and Crimea), replacing Vladislav Surkov, his long-time competitor for the role. The next Normandy meeting is expected in April 2020, and Kyiv should be aware of the possible pitfalls.While Kozak is perceived by some as a more pragmatic and less aggressive counterpart, his past tells a different story. In fact, he was the architect of the long-term strategy for Moldova, which centred on the federalization of Moldova and the reincorporation of the separatist region of Transnistria into Moldova.The presence of Russian military forces stationed on the ground there amounts to ‘armed suasion’ – using a military presence to demand political concessions from Moldova. The so-called ‘Kozak memorandum’ – which de facto re-writes the constitution of Moldova – contains a detailed explanation of that strategy.Kozak could try to deliver a similar situation for Ukraine. Less emphasis is being put on specific terms (federalization vs. special status) but the overarching aims are unchanged since 2014, in the same way they have been in Moldova since 2003. Kozak is a man who can play the long game, while the team of the Ukrainian president chases quick successes without calculating long-term risks. This could be a dangerous combination.The ‘human-centric approach’ to resolving the conflict followed by President Zelenskyy is a double-edged sword. The focuses on humanitarian issues and readiness for big compromises are clear positive signals to Western partners and supporters of Zelenskyy’s Servant of the People party. But prioritizing humanitarian issues over national security considerations could easily lead Ukraine into a Russian trap, which does not so much rely on a massive military assault but envisages creeping control over Ukraine’s future as its ultimate goal. Full Article
ad Moldova in 2020 and Beyond: Challenges Ahead By feedproxy.google.com Published On :: Mon, 17 Feb 2020 10:00:02 +0000 Invitation Only Research Event 5 March 2020 - 2:00pm to 3:30pm Chatham House | 10 St James's Square | London | SW1Y 4LE Event participants Maia Sandu, President, Action and Solidarity Party; Prime Minister of Moldova (June-November 2019)Chair: Cristina Gherasimov, Research Fellow, German Council on Foreign Relations; Academy Associate, Russia and Eurasia Programme, Chatham House After a tumultuous 2019 when Moldova witnessed the end of the Plahotniuc era, the country seems bound for an equally difficult year ahead. Increasing international isolation, a temporary working coalition between the Socialists and the Democrats, concentration of power and resources in the hands of President Igor Dodon, and presidential elections in autumn are among the ordeals to be discussed at this event. Ms Sandu will assess how Moldova can move beyond these challenges and return to a path for sustainable democratic reform. Department/project Russia and Eurasia Programme Anna Morgan Administrator, Ukraine Forum +44 (0)20 7389 3274 Email Full Article
ad Deficiency in ZMPSTE24 and resulting farnesyl-prelamin A accumulation only modestly affect mouse adipose tissue stores [Research Articles] By feedproxy.google.com Published On :: 2020-03-01T00:06:33-08:00 Zinc metallopeptidase STE24 (ZMPSTE24) is essential for the conversion of farnesyl–prelamin A to mature lamin A, a key component of the nuclear lamina. In the absence of ZMPSTE24, farnesyl–prelamin A accumulates in the nucleus and exerts toxicity, causing a variety of disease phenotypes. By ~4 months of age, both male and female Zmpste24–/– mice manifest a near-complete loss of adipose tissue, but it has never been clear whether this phenotype is a direct consequence of farnesyl–prelamin A toxicity in adipocytes. To address this question, we generated a conditional knockout Zmpste24 allele and used it to create adipocyte-specific Zmpste24–knockout mice. To boost farnesyl–prelamin A levels, we bred in the "prelamin A–only" Lmna allele. Gene expression, immunoblotting, and immunohistochemistry experiments revealed that adipose tissue in these mice had decreased Zmpste24 expression along with strikingly increased accumulation of prelamin A. In male mice, Zmpste24 deficiency in adipocytes was accompanied by modest changes in adipose stores (an 11% decrease in body weight, a 23% decrease in body fat mass, and significantly smaller gonadal and inguinal white adipose depots). No changes in adipose stores were detected in female mice, likely because prelamin A expression in adipose tissue is lower in female mice. Zmpste24 deficiency in adipocytes did not alter the number of macrophages in adipose tissue, nor did it alter plasma levels of glucose, triglycerides, or fatty acids. We conclude that ZMPSTE24 deficiency in adipocytes, and the accompanying accumulation of farnesyl–prelamin A, reduces adipose tissue stores, but only modestly and only in male mice. Full Article
ad Lithium ion adduction enables UPLC-MS/MS-based analysis of multi-class 3-hydroxyl group-containing keto-steroids [Methods] By feedproxy.google.com Published On :: 2020-04-01T00:05:29-07:00 Steroids that contain a 3-hydroxyl group (3-OH steroids) are widely distributed in nature. During analysis with ESI-MS, they easily become dehydrated while in the protonated form, resulting in the production of several precursor ions and leading to low sensitivity of detection. To address this analytical challenge, here, we developed a method for the quantitation of 3-OH steroids by LC-MS/MS coupled with post-column addition of lithium (Li) ions to the mobile phase. The Li ion has a high affinity for the keto group of steroids, stabilizing their structures during ionization and permitting detection of analytes exclusively as the lithiated form. This not only improved the intensities of the precursor ions, but also promoted the formation of typical lithiated fragment ions. This improvement made the quantitation by multiple reaction monitoring more sensitive and reliable, as evidenced by 1.53–188 times enhanced detection sensitivity of 13 steroids that contained at least one keto and two hydroxyl groups or one keto and one 5-olefinic double bond, among 16 different 3-OH steroids. We deployed our newly developed method for profiling steroids in mouse brain tissue and identified six steroids in one tissue sample. Among these, 16-hydroxyestrone, tetrahydrocorticosterone, and 17α-hydroxypregnenolone were detected for the first time in the mouse brain. In summary, the method described here enables the detection of lithiated steroids by LC-MS/MS, including three 3-OH steroids not previously reported in the mouse brain. We anticipate that this new method may allow the determination of 3-OH steroids in different brain regions. Full Article
ad Schnyder corneal dystrophy-associated UBIAD1 is defective in MK-4 synthesis and resists autophagy-mediated degradation [Research Articles] By feedproxy.google.com Published On :: 2020-05-01T00:05:27-07:00 The autosomal dominant disorder Schnyder corneal dystrophy (SCD) is caused by mutations in UbiA prenyltransferase domain-containing protein-1 (UBIAD1), which uses geranylgeranyl pyrophosphate (GGpp) to synthesize the vitamin K2 subtype menaquinone-4 (MK-4). SCD is characterized by opacification of the cornea, owing to aberrant build-up of cholesterol in the tissue. We previously discovered that sterols stimulate association of UBIAD1 with ER-localized HMG-CoA reductase, which catalyzes a rate-limiting step in the synthesis of cholesterol and nonsterol isoprenoids, including GGpp. Binding to UBIAD1 inhibits sterol-accelerated ER-associated degradation (ERAD) of reductase and permits continued synthesis of GGpp in cholesterol-replete cells. GGpp disrupts UBIAD1-reductase binding and thereby allows for maximal ERAD of reductase as well as ER-to-Golgi translocation of UBIAD1. SCD-associated UBIAD1 is refractory to GGpp-mediated dissociation from reductase and remains sequestered in the ER to inhibit ERAD. Here, we report development of a biochemical assay for UBIAD1-mediated synthesis of MK-4 in isolated membranes and intact cells. Using this assay, we compared enzymatic activity of WT UBIAD1 with that of SCD-associated variants. Our studies revealed that SCD-associated UBIAD1 exhibited reduced MK-4 synthetic activity, which may result from its reduced affinity for GGpp. Sequestration in the ER protects SCD-associated UBIAD1 from autophagy and allows intracellular accumulation of the mutant protein, which amplifies the inhibitory effect on reductase ERAD. These findings have important implications not only for the understanding of SCD etiology but also for the efficacy of cholesterol-lowering statin therapy, which becomes limited, in part, because of UBIAD1-mediated inhibition of reductase ERAD. Full Article
ad Problem Notes for SAS®9 - 65938: Incorrect values might be written to Hadoop for columns defined with the BIGINT data type By feedproxy.google.com Published On :: Fri, 8 May 2020 10:20:46 EST Large numeric values consisting of 16 digits in SAS might be incorrect when written to Hadoop for columns defined with the BIGINT data type. This problem was introduced in SAS 9 Full Article HADOOP+SAS/ACCESS+Interface+to+Hadoop
ad Problem Notes for SAS®9 - 65900: Registering an Oracle table to the metadata might fail and generate an error By feedproxy.google.com Published On :: Fri, 8 May 2020 09:38:11 EST When you register an Oracle table to the metadata, it might fail and generate an error similar to the following: "ERROR: An exception has been encountered...ERROR: Read Access Violation METALIB..." Full Article METADATASRV+SAS+Metadata+Server
ad Problem Notes for SAS®9 - 35066: When a bulk-loading process fails with "SQL*Loader 2026" error, error message appears as a warning in the SAS log By feedproxy.google.com Published On :: Thu, 7 May 2020 17:15:19 EST If a bulk-loading process fails when you use SAS with SAS/ACCESS Interface to Oracle, you will receive the warning: "WARNING: All or some rows were rejected/discarded.: The actual error is "SQL*Loader-2026: The load was aborted because SQL Full Article ORACLE+SAS/ACCESS+Interface+to+Oracle
ad Problem Notes for SAS®9 - 65834: PROC METADATA returns various errors when the input contains certain multi-byte characters By feedproxy.google.com Published On :: Thu, 7 May 2020 17:12:13 EST The METADATA procedure might return an error similar to one of the following: ERROR: Missing root element definition. Full Article BASE+Base+SAS
ad Problem Notes for SAS®9 - 64285: The SCD Type 2 Loader transformation in SAS Data Integration Studio generates "ERROR 22-322: Syntax error, expecting one of the following:..." By feedproxy.google.com Published On :: Wed, 6 May 2020 12:38:17 EST If your business key column is a name literal, like " business key "n, a syntax error occurs when that variable name does not follow standard SAS naming conventions. Full Article DATABUILDER+SAS+Data+Integration+Studio
ad Problem Notes for SAS®9 - 65922: Trying to read a Google BigQuery table that contains a variable defined as an array might result in a panic error and SAS shutting down By feedproxy.google.com Published On :: Wed, 6 May 2020 10:30:19 EST Trying to read a Google BigQuery table that contains a variable that is defined as an array of records might result in an error and cause SAS to shut down. This issue occurs when one of the variables contained in Full Article BIGQUERY+SAS/ACCESS+Interface+to+Google+
ad Problem Notes for SAS®9 - 65031: Grid options set mappings are returned based on which option set is the first in the metadata search chain By feedproxy.google.com Published On :: Tue, 5 May 2020 15:04:46 EST When users are defined in multiple groups associated with grid options set mappings, the first grid option set that is returned by the metadata search chain takes precedence. Only one grid options set mapping is used Full Article GRIDMGR+SAS+Grid+Manager
ad Problem Notes for SAS®9 - 65886: Trying to bulk load data into a Google BigQuery database might result in an error By feedproxy.google.com Published On :: Fri, 1 May 2020 10:00:17 EST When you bulk load data into a Google BigQuery database, you might encounter this error: "Error while reading data, error message: CSV table encountered too many errors, giving up...Error detected while parsing row starting at position: 0...Data Full Article BIGQUERY+SAS/ACCESS+Interface+to+Google+
ad Problem Notes for SAS®9 - 65898: A misleading SASTRACE message appears in the log when you insert a row into an Oracle table using SAS/ACCESS Interface to Oracle with DBIDIRECTEXEC By feedproxy.google.com Published On :: Thu, 30 Apr 2020 13:52:24 EST When you add one row to an Oracle table using DBIDIRECTEXEC, you see the following misleading trace message: "ORACLE: 4294967296 rows inserted/updated/deleted." You should see something similar to the following: "ORACLE: 1 rows inserte Full Article ORACLE+SAS/ACCESS+Interface+to+Oracle
ad Problem Notes for SAS®9 - 65883: SAS Workflow Studio returns a "cannot load" error when you try to open the CECL_Cycle_AFS workflow template for SAS Solution for CECL By feedproxy.google.com Published On :: Mon, 27 Apr 2020 16:10:54 EST You might see the following error in SAS Workflow Studio when you try to open the CECL_Cycle_AFS workflow template that is shipped with SAS Solution for CECL: Full Article RGPBNDL+SAS+Risk+Governance+Framework
ad Spring brings vet leaders for blossoming Rays By mlb.mlb.com Published On :: Wed, 13 Feb 2019 13:12:50 EDT When Tyler Glasnow heard the news that the Rays were signing Charlie Morton, he couldn't help but get even more excited for the 2019 season. Full Article
ad Diaz aims to turn heads, cement everyday role By mlb.mlb.com Published On :: Mon, 18 Feb 2019 19:36:23 EDT When Yandy Diaz arrived at Rays camp on Sunday, he quickly established himself as the most muscular player inside the clubhouse. During Spring Training, his focus will be to establish himself as an everyday player. Full Article
ad Sternberg optimistic about 2019, Rays' stadium By mlb.mlb.com Published On :: Tue, 19 Feb 2019 17:49:38 EDT Rays principal owner Stuart Sternberg won't make any big prediction entering the 2019 season, but he still expressed a lot of enthusiasm during Tuesday's media session. Full Article
ad Advances in regenerative medicine for otolaryngology/head and neck surgery By feeds.bmj.com Published On :: Wednesday, April 29, 2020 - 09:50 Full Article
ad ADAM10 and ADAM17 proteases mediate proinflammatory cytokine-induced and constitutive cleavage of endomucin from the endothelial surface [Membrane Biology] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Contact between inflammatory cells and endothelial cells (ECs) is a crucial step in vascular inflammation. Recently, we demonstrated that the cell-surface level of endomucin (EMCN), a heavily O-glycosylated single-transmembrane sialomucin, interferes with the interactions between inflammatory cells and ECs. We have also shown that, in response to an inflammatory stimulus, EMCN is cleared from the cell surface by an unknown mechanism. In this study, using adenovirus-mediated overexpression of a tagged EMCN in human umbilical vein ECs, we found that treatment with tumor necrosis factor α (TNF-α) or the strong oxidant pervanadate leads to loss of cell-surface EMCN and increases the levels of the C-terminal fragment of EMCN 3- to 4-fold. Furthermore, treatment with the broad-spectrum matrix metalloproteinase inhibitor batimastat (BB94) or inhibition of ADAM metallopeptidase domain 10 (ADAM10) and ADAM17 with two small-molecule inhibitors, GW280264X and GI254023X, or with siRNA significantly reduced basal and TNFα-induced cell-surface EMCN cleavage. Release of the C-terminal fragment of EMCN by TNF-α treatment was blocked by chemical inhibition of ADAM10 alone or in combination with ADAM17. These results indicate that cell-surface EMCN undergoes constitutive cleavage and that TNF-α treatment dramatically increases this cleavage, which is mediated predominantly by ADAM10 and ADAM17. As endothelial cell-surface EMCN attenuates leukocyte–EC interactions during inflammation, we propose that EMCN is a potential therapeutic target to manage vascular inflammation. Full Article
ad Adipose Triglyceride Lipase is a Key Lipase for the Mobilization of Lipid Droplets in Human Beta Cells and Critical for the Maintenance of Syntaxin1a Level in Beta Cells By diabetes.diabetesjournals.org Published On :: 2020-03-31T14:12:19-07:00 Lipid droplets (LDs) are frequently increased when excessive lipid accumulation leads to cellular dysfunction. Distinct from mouse beta cells, LDs are prominent in human beta cells, however, the regulation of LD mobilization (lipolysis) in human beta cells remains unclear. We found that glucose increases lipolysis in non-diabetic human islets, but not in type 2 diabetic (T2D) islets, indicating dysregulation of lipolysis in T2D islets. Silencing adipose triglyceride lipase (ATGL) in human pseudoislets (shATGL) increased triglycerides, and the number and size of LDs indicating that ATGL is the principal lipase in human beta cells. In shATGL pseudoislets, biphasic glucose-stimulated insulin secretion (GSIS) and insulin secretion to IBMX and KCl were all reduced without altering oxygen consumption rate compared with scramble control. Like human islets, INS1 cells showed visible LDs, glucose responsive lipolysis, and impairment of GSIS after ATGL silencing. ATGL deficient INS1 cells and human pseudoislets showed reduced Stx1a, a key SNARE component. Proteasomal degradation of Stx1a was accelerated likely through reduced palmitoylation in ATGL deficient INS1 cells. Therefore, ATGL is responsible for LD mobilization in human beta cells and supports insulin secretion by stabilizing Stx1a. The dysregulated lipolysis may contribute to LD accumulation and beta cell dysfunction in T2D islets. Full Article
ad Adipose Triglyceride Lipase is a Key Lipase for the Mobilization of Lipid Droplets in Human Beta Cells and Critical for the Maintenance of Syntaxin1a Level in Beta Cells By diabetes.diabetesjournals.org Published On :: 2020-04-20T08:51:08-07:00 Lipid droplets (LDs) are frequently increased when excessive lipid accumulation leads to cellular dysfunction. Distinct from mouse beta cells, LDs are prominent in human beta cells, however, the regulation of LD mobilization (lipolysis) in human beta cells remains unclear. We found that glucose increases lipolysis in non-diabetic human islets, but not in type 2 diabetic (T2D) islets, indicating dysregulation of lipolysis in T2D islets. Silencing adipose triglyceride lipase (ATGL) in human pseudoislets (shATGL) increased triglycerides, and the number and size of LDs indicating that ATGL is the principal lipase in human beta cells. In shATGL pseudoislets, biphasic glucose-stimulated insulin secretion (GSIS) and insulin secretion to IBMX and KCl were all reduced without altering oxygen consumption rate compared with scramble control. Like human islets, INS1 cells showed visible LDs, glucose responsive lipolysis, and impairment of GSIS after ATGL silencing. ATGL deficient INS1 cells and human pseudoislets showed reduced Stx1a, a key SNARE component. Proteasomal degradation of Stx1a was accelerated likely through reduced palmitoylation in ATGL deficient INS1 cells. Therefore, ATGL is responsible for LD mobilization in human beta cells and supports insulin secretion by stabilizing Stx1a. The dysregulated lipolysis may contribute to LD accumulation and beta cell dysfunction in T2D islets. Full Article
ad Excitotoxicity and Overnutrition Additively Impair Metabolic Function and Identity of Pancreatic {beta}-cells By diabetes.diabetesjournals.org Published On :: 2020-04-24T09:55:27-07:00 A sustained increase in intracellular Ca2+ concentration (referred to herein as excitotoxicity), brought on by chronic metabolic stress, may contribute to pancreatic β-cell failure. To determine the additive effects of excitotoxicity and overnutrition on β-cell function and gene expression, we analyzed the impact of a high fat diet (HFD) on Abcc8 knock-out mice. Excitotoxicity caused β-cells to be more susceptible to HFD-induced impairment of glucose homeostasis, and these effects were mitigated by verapamil, a Ca2+ channel blocker. Excitotoxicity, overnutrition and the combination of both stresses caused similar but distinct alterations in the β-cell transcriptome, including additive increases in genes associated with mitochondrial energy metabolism, fatty acid β-oxidation and mitochondrial biogenesis, and their key regulator Ppargc1a. Overnutrition worsened excitotoxicity-induced mitochondrial dysfunction, increasing metabolic inflexibility and mitochondrial damage. In addition, excitotoxicity and overnutrition, individually and together, impaired both β-cell function and identity by reducing expression of genes important for insulin secretion, cell polarity, cell junction, cilia, cytoskeleton, vesicular trafficking, and regulation of β-cell epigenetic and transcriptional program. Sex had an impact on all β-cell responses, with male animals exhibiting greater metabolic stress-induced impairments than females. Together, these findings indicate that a sustained increase in intracellular Ca2+, by altering mitochondrial function and impairing β-cell identity, augments overnutrition-induced β-cell failure. Full Article
ad Elevated First-Trimester Neutrophil Count Is Closely Associated with the Development of Maternal Gestational Diabetes Mellitus and Adverse Pregnancy Outcomes By diabetes.diabetesjournals.org Published On :: 2020-04-24T14:58:49-07:00 Chronic low-grade inflammation plays a central role in the pathophysiology of gestational diabetes mellitus (GDM). In order to investigate the ability of different inflammatory blood cell parameters in predicting the development of GDM and pregnancy outcomes, 258 women with GDM and 1154 women without were included in this retrospective study. First-trimester neutrophil count outperformed white blood cell (WBC) count, and neutrophil-to-lymphocyte ratio (NLR) in the predictability for GDM. Subjects were grouped based on tertiles of neutrophil count during their first-trimester pregnancy. The results showed that as the neutrophil count increased, there was a step-wise increase in GDM incidence, as well as glucose and glycosylated hemoglobin (HbA1c) level, Homeostasis Model Assessment for Insulin Resistance (HOMA-IR), macrosomia incidence and newborn weight. Neutrophil count was positively associated with pre-pregnancy Body Mass Index (BMI), HOMA-IR and newborn weight. Additionally, neutrophil count was an independent risk factor for the development of GDM, regardless of the history of GDM. Spline regression showed that there was a significant linear association between GDM incidence and continuous neutrophil count when it exceeded 5.0 x 109/L. This work suggested that first-trimester neutrophil count is closely associated with the development of GDM and adverse pregnancy outcomes. Full Article
ad Glucose-Stimulated Insulin Secretion Fundamentally Requires H2O2 Signaling by NADPH Oxidase 4 By diabetes.diabetesjournals.org Published On :: 2020-04-24T18:07:35-07:00 NADPH facilitates glucose-stimulated insulin secretion (GSIS) in pancreatic islet (PI) β-cells by an as yet unknown mechanism. We found NADPH oxidase, isoform-4 (NOX4), to be the major producer of cytosolic H2O2, essential for GSIS, while the increase in ATP/ADP alone was insufficient. The fast GSIS phase was absent in PIs from NOX4-null, β-cell-specific knockout mice (NOX4βKO) (not NOX2KO), and NOX4-silenced or catalase-overexpressing INS-1E cells. Lentiviral NOX4 overexpression or H2O2 rescued GSIS in PIs from NOX4βKO mice. NOX4 silencing suppressed Ca2+ oscillations and the patch-clamped ATP-sensitive potassium channel (KATP) opened more frequently at high glucose. Mitochondrial H2O2, decreasing upon GSIS, provided an alternative redox signaling when 2-oxo-isocaproate or fatty acid oxidation formed superoxide by electron-transport flavoprotein:Q-oxidoreductase. Unlike GSIS, this ceased with mitochondrial antioxidant SkQ1. Both NOX4KO and NOX4βKO strains exhibited impaired glucose tolerance and peripheral insulin resistance. Thus the redox signaling previously suggested to cause β-cell-self-checking – hypothetically induces insulin resistance when absent. In conclusion, ATP plus H2O2 elevations constitute an essential switch-on signal of insulin exocytosis for glucose and branched-chain oxoacids as secretagogues (partly for fatty acids). Redox signaling could be impaired by cytosolic antioxidants, hence those targeting mitochondria should be preferred for clinical applications to treat (pre)diabetes at any stage. Full Article
ad Transketolase Deficiency in Adipose Tissues Protects Mice From Diet-Induced Obesity by Promoting Lipolysis By diabetes.diabetesjournals.org Published On :: 2020-04-24T18:07:35-07:00 Obesity has recently become a prevalent health threat worldwide. Although emerging evidence has suggested a strong link between the pentose phosphate pathway (PPP) and obesity, the role of transketolase (TKT), an enzyme in the non-oxidative branch of the PPP which connects PPP and glycolysis, remains obscure in adipose tissues. In this study, we specifically delete TKT in mouse adipocytes and find no obvious phenotype upon normal diet feeding. However, adipocyte TKT abrogation attenuates high fat diet (HFD)-induced obesity, reduces hepatic steatosis, improves glucose tolerance, alleviates insulin resistance and increases energy expenditure. Mechanistically, TKT deficiency accumulates non-oxidative PPP metabolites, decreases glycolysis and pyruvate input into the mitochondria, leading to increased lipolytic enzyme gene expression and enhanced lipolysis, fatty acid oxidation and mitochondrial respiration. Therefore, our data not only identify a novel role of TKT in regulating lipolysis and obesity, but also suggest limiting glucose-derived carbon into the mitochondria induces lipid catabolism and energy expenditure. Full Article
ad Nutrient-Induced Metabolic Stress, Adaptation, Detoxification, and Toxicity in the Pancreatic {beta}-Cell By diabetes.diabetesjournals.org Published On :: 2020-02-20T11:55:30-08:00 Paraphrasing the Swiss physician and father of toxicology Paracelsus (1493–1541) on chemical agents used as therapeutics, "the dose makes the poison," it is now realized that this aptly applies to the calorigenic nutrients. The case here is the pancreatic islet β-cell presented with excessive levels of nutrients such as glucose, lipids, and amino acids. The short-term effects these nutrients exert on the β-cell are enhanced insulin biosynthesis and secretion and changes in glucose sensitivity. However, chronic fuel surfeit triggers additional compensatory and adaptive mechanisms by β-cells to cope with the increased insulin demand or to protect itself. When these mechanisms fail, toxicity due to the nutrient surplus ensues, leading to β-cell dysfunction, dedifferentiation, and apoptosis. The terms glucotoxicity, lipotoxicity, and glucolipotoxicity have been widely used, but there is some confusion as to what they mean precisely and which is most appropriate for a given situation. Here we address the gluco-, lipo-, and glucolipo-toxicities in β-cells by assessing the evidence both for and against each of them. We also discuss potential mechanisms and defend the view that many of the identified "toxic" effects of nutrient excess, which may also include amino acids, are in fact beneficial adaptive processes. In addition, candidate fuel-excess detoxification pathways are evaluated. Finally, we propose that a more general term should be used for the in vivo situation of overweight-associated type 2 diabetes reflecting both the adaptive and toxic processes to mixed calorigenic nutrients excess: "nutrient-induced metabolic stress" or, in brief, "nutri-stress." Full Article
ad The mitochondrial protein PGAM5 suppresses energy consumption in brown adipocytes by repressing expression of uncoupling protein 1 [Metabolism] By feedproxy.google.com Published On :: 2020-04-24T06:08:45-07:00 Accumulating evidence suggests that brown adipose tissue (BAT) is a potential therapeutic target for managing obesity and related diseases. PGAM family member 5, mitochondrial serine/threonine protein phosphatase (PGAM5), is a protein phosphatase that resides in the mitochondria and regulates many biological processes, including cell death, mitophagy, and immune responses. Because BAT is a mitochondria-rich tissue, we have hypothesized that PGAM5 has a physiological function in BAT. We previously reported that PGAM5-knockout (KO) mice are resistant to severe metabolic stress. Importantly, lipid accumulation is suppressed in PGAM5-KO BAT, even under unstressed conditions, raising the possibility that PGAM5 deficiency stimulates lipid consumption. However, the mechanism underlying this observation is undetermined. Here, using an array of biochemical approaches, including quantitative RT-PCR, immunoblotting, and oxygen consumption assays, we show that PGAM5 negatively regulates energy expenditure in brown adipocytes. We found that PGAM5-KO brown adipocytes have an enhanced oxygen consumption rate and increased expression of uncoupling protein 1 (UCP1), a protein that increases energy consumption in the mitochondria. Mechanistically, we found that PGAM5 phosphatase activity and intramembrane cleavage are required for suppression of UCP1 activity. Furthermore, utilizing a genome-wide siRNA screen in HeLa cells to search for regulators of PGAM5 cleavage, we identified a set of candidate genes, including phosphatidylserine decarboxylase (PISD), which catalyzes the formation of phosphatidylethanolamine at the mitochondrial membrane. Taken together, these results indicate that PGAM5 suppresses mitochondrial energy expenditure by down-regulating UCP1 expression in brown adipocytes and that its phosphatase activity and intramembrane cleavage are required for UCP1 suppression. Full Article
ad Catabolic degradation of endothelial VEGFA via autophagy [Glycobiology and Extracellular Matrices] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 Extracellular matrix-evoked angiostasis and autophagy within the tumor microenvironment represent two critical, but unconnected, functions of the small leucine-rich proteoglycan, decorin. Acting as a partial agonist of vascular endothelial growth factor 2 (VEGFR2), soluble decorin signals via the energy sensing protein, AMP-activated protein kinase (AMPK), in the autophagic degradation of intracellular vascular endothelial growth factor A (VEGFA). Here, we discovered that soluble decorin evokes intracellular catabolism of endothelial VEGFA that is mechanistically independent of mTOR, but requires an autophagic regulator, paternally expressed gene 3 (PEG3). We found that administration of autophagic inhibitors such as chloroquine or bafilomycin A1, or depletion of autophagy-related 5 (ATG5), results in accumulation of intracellular VEGFA, indicating that VEGFA is a basal autophagic substrate. Mechanistically, decorin increased the VEGFA clearance rate by augmenting autophagic flux, a process that required RAB24 member RAS oncogene family (RAB24), a small GTPase that facilitates the disposal of autophagic compartments. We validated these findings by demonstrating the physiological relevance of this process in vivo. Mice starved for 48 h exhibited a sharp decrease in overall cardiac and aortic VEGFA that could be blocked by systemic chloroquine treatment. Thus, our findings reveal a unified mechanism for the metabolic control of endothelial VEGFA for autophagic clearance in response to decorin and canonical pro-autophagic stimuli. We posit that the VEGFR2/AMPK/PEG3 axis integrates the anti-angiogenic and pro-autophagic bioactivities of decorin as the molecular basis for tumorigenic suppression. These results support future therapeutic use of decorin as a next-generation protein therapy to combat cancer. Full Article
ad The focal adhesion protein kindlin-2 controls mitotic spindle assembly by inhibiting histone deacetylase 6 and maintaining {alpha}-tubulin acetylation [Signal Transduction] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 Kindlins are focal adhesion proteins that regulate integrin activation and outside-in signaling. The kindlin family consists of three members, kindlin-1, -2, and -3. Kindlin-2 is widely expressed in multiple cell types, except those from the hematopoietic lineage. A previous study has reported that the Drosophila Fit1 protein (an ortholog of kindlin-2) prevents abnormal spindle assembly; however, the mechanism remains unknown. Here, we show that kindlin-2 maintains spindle integrity in mitotic human cells. The human neuroblastoma SH-SY5Y cell line expresses only kindlin-2, and we found that when SH-SY5Y cells are depleted of kindlin-2, they exhibit pronounced spindle abnormalities and delayed mitosis. Of note, acetylation of α-tubulin, which maintains microtubule flexibility and stability, was diminished in the kindlin-2–depleted cells. Mechanistically, we found that kindlin-2 maintains α-tubulin acetylation by inhibiting the microtubule-associated deacetylase histone deacetylase 6 (HDAC6) via a signaling pathway involving AKT Ser/Thr kinase (AKT)/glycogen synthase kinase 3β (GSK3β) or paxillin. We also provide evidence that prolonged hypoxia down-regulates kindlin-2 expression, leading to spindle abnormalities not only in the SH-SY5Y cell line, but also cell lines derived from colon and breast tissues. The findings of our study highlight that kindlin-2 regulates mitotic spindle assembly and that this process is perturbed in cancer cells in a hypoxic environment. Full Article
ad The cytochrome P450 enzyme CYP24A1 increases proliferation of mutant KRAS-dependent lung adenocarcinoma independent of its catalytic activity [Cell Biology] By feedproxy.google.com Published On :: 2020-05-01T00:06:09-07:00 We previously reported that overexpression of cytochrome P450 family 24 subfamily A member 1 (CYP24A1) increases lung cancer cell proliferation by activating RAS signaling and that CYP24A1 knockdown inhibits tumor growth. However, the mechanism of CYP24A1-mediated cancer cell proliferation remains unclear. Here, we conducted cell synchronization and biochemical experiments in lung adenocarcinoma cells, revealing a link between CYP24A1 and anaphase-promoting complex (APC), a key cell cycle regulator. We demonstrate that CYP24A1 expression is cell cycle–dependent; it was higher in the G2-M phase and diminished upon G1 entry. CYP24A1 has a functional destruction box (D-box) motif that allows binding with two APC adaptors, CDC20-homologue 1 (CDH1) and cell division cycle 20 (CDC20). Unlike other APC substrates, however, CYP24A1 acted as a pseudo-substrate, inhibiting CDH1 activity and promoting mitotic progression. Conversely, overexpression of a CYP24A1 D-box mutant compromised CDH1 binding, allowing CDH1 hyperactivation, thereby hastening degradation of its substrates cyclin B1 and CDC20, and accumulation of the CDC20 substrate p21, prolonging mitotic exit. These activities also occurred with a CYP24A1 isoform 2 lacking the catalytic cysteine (Cys-462), suggesting that CYP24A1's oncogenic potential is independent of its catalytic activity. CYP24A1 degradation reduced clonogenic survival of mutant KRAS-driven lung cancer cells, and calcitriol treatment increased CYP24A1 levels and tumor burden in Lsl-KRASG12D mice. These results disclose a catalytic activity-independent growth-promoting role of CYP24A1 in mutant KRAS-driven lung cancer. This suggests that CYP24A1 could be therapeutically targeted in lung cancers in which its expression is high. Full Article
ad SUMOylation of the transcription factor ZFHX3 at Lys-2806 requires SAE1, UBC9, and PIAS2 and enhances its stability and function in cell proliferation [Protein Synthesis and Degradation] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 SUMOylation is a posttranslational modification (PTM) at a lysine residue and is crucial for the proper functions of many proteins, particularly of transcription factors, in various biological processes. Zinc finger homeobox 3 (ZFHX3), also known as AT motif-binding factor 1 (ATBF1), is a large transcription factor that is active in multiple pathological processes, including atrial fibrillation and carcinogenesis, and in circadian regulation and development. We have previously demonstrated that ZFHX3 is SUMOylated at three or more lysine residues. Here, we investigated which enzymes regulate ZFHX3 SUMOylation and whether SUMOylation modulates ZFHX3 stability and function. We found that SUMO1, SUMO2, and SUMO3 each are conjugated to ZFHX3. Multiple lysine residues in ZFHX3 were SUMOylated, but Lys-2806 was the major SUMOylation site, and we also found that it is highly conserved among ZFHX3 orthologs from different animal species. Using molecular analyses, we identified the enzymes that mediate ZFHX3 SUMOylation; these included SUMO1-activating enzyme subunit 1 (SAE1), an E1-activating enzyme; SUMO-conjugating enzyme UBC9 (UBC9), an E2-conjugating enzyme; and protein inhibitor of activated STAT2 (PIAS2), an E3 ligase. Multiple analyses established that both SUMO-specific peptidase 1 (SENP1) and SENP2 deSUMOylate ZFHX3. SUMOylation at Lys-2806 enhanced ZFHX3 stability by interfering with its ubiquitination and proteasomal degradation. Functionally, Lys-2806 SUMOylation enabled ZFHX3-mediated cell proliferation and xenograft tumor growth of the MDA-MB-231 breast cancer cell line. These findings reveal the enzymes involved in, and the functional consequences of, ZFHX3 SUMOylation, insights that may help shed light on ZFHX3's roles in various cellular and pathophysiological processes. Full Article
ad A kinesin adapter directly mediates dendritic mRNA localization during neural development in mice [Neurobiology] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Motor protein-based active transport is essential for mRNA localization and local translation in animal cells, yet how mRNA granules interact with motor proteins remains poorly understood. Using an unbiased yeast two–hybrid screen for interactions between murine RNA-binding proteins (RBPs) and motor proteins, here we identified protein interaction with APP tail-1 (PAT1) as a potential direct adapter between zipcode-binding protein 1 (ZBP1, a β-actin RBP) and the kinesin-I motor complex. The amino acid sequence of mouse PAT1 is similar to that of the kinesin light chain (KLC), and we found that PAT1 binds to KLC directly. Studying PAT1 in mouse primary hippocampal neuronal cultures from both sexes and using structured illumination microscopic imaging of these neurons, we observed that brain-derived neurotrophic factor (BDNF) enhances co-localization of dendritic ZBP1 and PAT1 within granules that also contain kinesin-I. PAT1 is essential for BDNF-stimulated neuronal growth cone development and dendritic protrusion formation, and we noted that ZBP1 and PAT1 co-locate along with β-actin mRNA in actively transported granules in living neurons. Acute disruption of the PAT1–ZBP1 interaction in neurons with PAT1 siRNA or a dominant-negative ZBP1 construct diminished localization of β-actin mRNA but not of Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα) mRNA in dendrites. The aberrant β-actin mRNA localization resulted in abnormal dendritic protrusions and growth cone dynamics. These results suggest a critical role for PAT1 in BDNF-induced β-actin mRNA transport during postnatal development and reveal a new molecular mechanism for mRNA localization in vertebrates. Full Article
ad Endorepellin evokes an angiostatic stress signaling cascade in endothelial cells [Glycobiology and Extracellular Matrices] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Endorepellin, the C-terminal fragment of the heparan sulfate proteoglycan perlecan, influences various signaling pathways in endothelial cells by binding to VEGFR2. In this study, we discovered that soluble endorepellin activates the canonical stress signaling pathway consisting of PERK, eIF2α, ATF4, and GADD45α. Specifically, endorepellin evoked transient activation of VEGFR2, which, in turn, phosphorylated PERK at Thr980. Subsequently, PERK phosphorylated eIF2α at Ser51, upregulating its downstream effector proteins ATF4 and GADD45α. RNAi-mediated knockdown of PERK or eIF2α abrogated the endorepellin-mediated up-regulation of GADD45α, the ultimate effector protein of this stress signaling cascade. To functionally validate these findings, we utilized an ex vivo model of angiogenesis. Exposure of the aortic rings embedded in 3D fibrillar collagen to recombinant endorepellin for 2–4 h activated PERK and induced GADD45α vis à vis vehicle-treated counterparts. Similar effects were obtained with the established cellular stress inducer tunicamycin. Notably, chronic exposure of aortic rings to endorepellin for 7–9 days markedly suppressed vessel sprouting, an angiostatic effect that was rescued by blocking PERK kinase activity. Our findings unravel a mechanism by which an extracellular matrix protein evokes stress signaling in endothelial cells, which leads to angiostasis. Full Article
ad The testis-specific LINC component SUN3 is essential for sperm head shaping during mouse spermiogenesis [Cell Biology] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Sperm head shaping is a key event in spermiogenesis and is tightly controlled via the acrosome–manchette network. Linker of nucleoskeleton and cytoskeleton (LINC) complexes consist of Sad1 and UNC84 domain–containing (SUN) and Klarsicht/ANC-1/Syne-1 homology (KASH) domain proteins and form conserved nuclear envelope bridges implicated in transducing mechanical forces from the manchette to sculpt sperm nuclei into a hook-like shape. However, the role of LINC complexes in sperm head shaping is still poorly understood. Here we assessed the role of SUN3, a testis-specific LINC component harboring a conserved SUN domain, in spermiogenesis. We show that CRISPR/Cas9-generated Sun3 knockout male mice are infertile, displaying drastically reduced sperm counts and a globozoospermia-like phenotype, including a missing, mislocalized, or fragmented acrosome, as well as multiple defects in sperm flagella. Further examination revealed that the sperm head abnormalities are apparent at step 9 and that the sperm nuclei fail to elongate because of the absence of manchette microtubules and perinuclear rings. These observations indicate that Sun3 deletion likely impairs the ability of the LINC complex to transduce the cytoskeletal force to the nuclear envelope, required for sperm head elongation. We also found that SUN3 interacts with SUN4 in mouse testes and that the level of SUN4 proteins is drastically reduced in Sun3-null mice. Altogether, our results indicate that SUN3 is essential for sperm head shaping and male fertility, providing molecular clues regarding the underlying pathology of the globozoospermia-like phenotype. Full Article
ad 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
ad The streptococcal multidomain fibrillar adhesin CshA has an elongated polymeric architecture [Microbiology] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 The cell surfaces of many bacteria carry filamentous polypeptides termed adhesins that enable binding to both biotic and abiotic surfaces. Surface adherence is facilitated by the exquisite selectivity of the adhesins for their cognate ligands or receptors and is a key step in niche or host colonization and pathogenicity. Streptococcus gordonii is a primary colonizer of the human oral cavity and an opportunistic pathogen, as well as a leading cause of infective endocarditis in humans. The fibrillar adhesin CshA is an important determinant of S. gordonii adherence, forming peritrichous fibrils on its surface that bind host cells and other microorganisms. CshA possesses a distinctive multidomain architecture comprising an N-terminal target-binding region fused to 17 repeat domains (RDs) that are each ∼100 amino acids long. Here, using structural and biophysical methods, we demonstrate that the intact CshA repeat region (CshA_RD1–17, domains 1–17) forms an extended polymeric monomer in solution. We recombinantly produced a subset of CshA RDs and found that they differ in stability and unfolding behavior. The NMR structure of CshA_RD13 revealed a hitherto unreported all β-fold, flanked by disordered interdomain linkers. These findings, in tandem with complementary hydrodynamic studies of CshA_RD1–17, indicate that this polypeptide possesses a highly unusual dynamic transitory structure characterized by alternating regions of order and disorder. This architecture provides flexibility for the adhesive tip of the CshA fibril to maintain bacterial attachment that withstands shear forces within the human host. It may also help mitigate deleterious folding events between neighboring RDs that share significant structural identity without compromising mechanical stability. Full Article
ad The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold [Protein Structure and Folding] By feedproxy.google.com Published On :: 2020-05-08T03:41:14-07:00 Type IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modeling analyses suggest that the unusual structure of ComGC is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species. Full Article
ad Pancreas Pathology of Latent Autoimmune Diabetes in Adults (LADA) in Patients and in a LADA Rat Model Compared With Type 1 Diabetes By diabetes.diabetesjournals.org Published On :: 2020-04-01 Anne JörnsApr 1, 2020; 69:624-633Islet Studies Full Article