sig CBD News: The guidance addresses a major pathway for introduction and spread of invasive alien species, as a significant percentage of global invasive introductions result from pets, aquarium and terrarium species that escape from confined conditions and By www.cbd.int Published On :: Fri, 10 Oct 2014 00:00:00 GMT Full Article
sig CBD News: The signature on 15 November 2014 of a Memorandum of Understanding between the two organisations will ensure joint implementation of the Pacific region's Framework for Nature Conservation and Protected Areas in the Pacific Island Region 2014 By www.cbd.int Published On :: Tue, 25 Nov 2014 00:00:00 GMT Full Article
sig CBD News: CBD Expert Workshop to Prepare Practical Guidance on Preventing and Mitigating the Significant Adverse Impacts of Marine Debris on Marine and Coastal Biodiversity and Habitats, Baltimore, United States of America, 2 to 4 December 2014 By www.cbd.int Published On :: Tue, 02 Dec 2014 00:00:00 GMT Full Article
sig CBD News: Montreal/Kolkata, 13 February 2015 - A ground-breaking report on biodiversity and health, launched today at the 14th World Congress on Public Health, in Kolkata, India, shows the significant contribution of biodiversity and ecosystem services t By www.cbd.int Published On :: Fri, 13 Feb 2015 00:00:00 GMT Full Article
sig CBD News: Statement by Mr. Braulio F. de Souza Dias, CBD Executive Secretary, at the opening of the CBD Regional Workshop to Facilitate the Description of Ecologically or Biologically Significant Marine Areas (EBSAs) in the North-East Indian Ocean Region, By www.cbd.int Published On :: Mon, 23 Mar 2015 00:00:00 GMT Full Article
sig CBD News: On 21 March 2015 the CBD Secretariat and the Korea Forest Service signed a Memorandum of Understanding for implementation of the Forest Ecosystem Restoration Initiative. By www.cbd.int Published On :: Tue, 24 Mar 2015 00:00:00 GMT Full Article
sig CBD News: The Republic of Korea and the Secretariat of the Convention on Biological Diversity (CBD), with the purpose of promoting technical and scientific co-operation and to support achievement of the goals and targets of the Convention, have today sign By www.cbd.int Published On :: Tue, 19 May 2015 00:00:00 GMT Full Article
sig CBD News: Statement by the Executive Secretary at the opening of the CBD Regional Workshop to Facilitate the Description of Ecologically or Biologically Significant Marine Areas (EBSAs) in the Seas of East Asia, Xiamen, China, 14 - 18 December 2015 By www.cbd.int Published On :: Mon, 14 Dec 2015 00:00:00 GMT Full Article
sig CBD News: This year, International Mother Earth Day coincides with the signing ceremony for the Paris Agreement on Climate Change at UN Headquarters in New York, where world governments will demonstrate their commitment to meet the challenges of climate c By www.cbd.int Published On :: Tue, 19 Apr 2016 00:00:00 GMT Full Article
sig CBD News: While many countries have made significant advances, indigenous peoples continue to face challenges in accessing their right to education, in particular their right to access a culturally appropriate education inclusive of their histories, world By www.cbd.int Published On :: Tue, 09 Aug 2016 00:00:00 GMT Full Article
sig CBD News: The Secretariat of the Convention on Biodiversity (SCBD) and WWF International have signed an MoU to collaborate in implementing CBD's Global Communications Strategy together with CBD Parties, partners and the broader conservation community By www.cbd.int Published On :: Wed, 14 Dec 2016 00:00:00 GMT Full Article
sig CBD News: This year's theme for International Women's Day highlights women in the changing world of work, and sets our collective sights on the objective of making gender equality a reality by 2030. By www.cbd.int Published On :: Wed, 08 Mar 2017 00:00:00 GMT Full Article
sig CBD News: The ten-year anniversary of the United Nations Declaration on the Rights of Indigenous Peoples presents a fitting opportunity to draw attention to the significant contribution of indigenous peoples to the conservation and sustainable use of the By www.cbd.int Published On :: Tue, 08 Aug 2017 00:00:00 GMT Full Article
sig CBD News: First 23 validated checklists from the Global Register of Introduced and Invasive Species highlighted in paper, signaling major step in delivering information to support national action against biological invasions. By www.gbif.org Published On :: Tue, 23 Jan 2018 00:00:00 GMT Full Article
sig CBD News: The ecologically or biologically significant marine areas (EBSA) booklet series provide snapshot summaries of the pages upon pages of data compiled by participating experts, to provide an inspiring overview of some of the most ecologically or bi By www.cbd.int Published On :: Fri, 22 Jun 2018 00:00:00 GMT Full Article
sig CBD News: A Memorandum of Cooperation (MoC) geared towards enhancing cooperation between the Secretariats of the Convention on Biological Diversity (CBD) and the FAO International Treaty on Plant Genetic Resources for Food and Agriculture was signed today By www.cbd.int Published On :: Mon, 09 Jul 2018 00:00:00 GMT Full Article
sig CBD Notification SCBD/SSSF/AS/SBG/JA/JG/88518 (2019-107): Expert Workshop to Identify Options for Modifying the Description of Ecologically or Biologically Significant Marine Areas (EBSAs) and Describing New EBSAs, 3 to 5 February 2020 - Brussels, Belgium By www.cbd.int Published On :: Wed, 27 Nov 2019 00:00:00 GMT Full Article
sig CBD Notification SCBD/OES/DAIN/FV/UN/SN/FD/88542 (2019-118): Launching of the First Phase of the Newly Designed Website By www.cbd.int Published On :: Mon, 23 Dec 2019 00:00:00 GMT Full Article
sig Mask production subsidies reassigned By www.news.gov.hk Published On :: Mon, 04 May 2020 00:00:00 +0800 The Commerce & Economic Development Bureau today announced that the subsidy quota for three mask production lines have been reassigned. Three production lines, previously approved under the Local Mask Production Subsidy Scheme, have withdrawn from the scheme, the Government said. The subsidy quota concerned has been allocated to SDL Skin (Asia), Safeguard HK and SwissTech. SDL Skin (Asia) has been approved for obtaining a subsidy for a second production line and is expected to supply an average of 1.6 million masks every month to the Government. The production line may receive a subsidy of up to $1 million. Safeguard HK has been approved for obtaining a subsidy for one production line and is expected to supply an average of 500,000 masks to the Government every month. The production line may receive up to $2 million. SwissTech has been approved for obtaining a subsidy for one production line and is expected to supply an average of 2 million masks every month to the Government and produce a further 1 million masks on average monthly for the local market. The production line may receive up to $3 million. It is estimated that when all 20 subsidised lines under the scheme are in full production, they will collectively supply 33.85 million masks to the Government and a further 7.15 million to the local market monthly. The companies which withdrew from the scheme were CareHK and Shang Manufactory. The Government did not sign agreements with or make disbursements to these firms. Full Article
sig Geometric designs in the snow by Simon Beck By www.ams.org Published On :: Tue, 21 Jan 2020 00:00:00 EST "Artist uses snow as canvas for massive geometrical designs," by Thomas Peipert, AP, January 16, 2020. Full Article
sig {gamma}-Hydroxybutyrate does not mediate glucose inhibition of glucagon secretion [Signal Transduction] By www.jbc.org Published On :: 2020-04-17T00:06:05-07:00 Hypersecretion of glucagon from pancreatic α-cells strongly contributes to diabetic hyperglycemia. Moreover, failure of α-cells to increase glucagon secretion in response to falling blood glucose concentrations compromises the defense against hypoglycemia, a common complication in diabetes therapy. However, the mechanisms underlying glucose regulation of glucagon secretion are poorly understood and likely involve both α-cell–intrinsic and intraislet paracrine signaling. Among paracrine factors, glucose-stimulated release of the GABA metabolite γ-hydroxybutyric acid (GHB) from pancreatic β-cells might mediate glucose suppression of glucagon release via GHB receptors on α-cells. However, the direct effects of GHB on α-cell signaling and glucagon release have not been investigated. Here, we found that GHB (4–10 μm) lacked effects on the cytoplasmic concentrations of the secretion-regulating messengers Ca2+ and cAMP in mouse α-cells. Glucagon secretion from perifused mouse islets was also unaffected by GHB at both 1 and 7 mm glucose. The GHB receptor agonist 3-chloropropanoic acid and the antagonist NCS-382 had no effects on glucagon secretion and did not affect stimulation of secretion induced by a drop in glucose from 7 to 1 mm. Inhibition of endogenous GHB formation with the GABA transaminase inhibitor vigabatrin also failed to influence glucagon secretion at 1 mm glucose and did not prevent the suppressive effect of 7 mm glucose. In human islets, GHB tended to stimulate glucagon secretion at 1 mm glucose, an effect mimicked by 3-chloropropanoic acid. We conclude that GHB does not mediate the inhibitory effect of glucose on glucagon secretion. Full Article
sig Biochemical and structural insights into how amino acids regulate pyruvate kinase muscle isoform 2 [Enzymology] By www.jbc.org Published On :: 2020-04-17T00:06:05-07:00 Pyruvate kinase muscle isoform 2 (PKM2) is a key glycolytic enzyme involved in ATP generation and critical for cancer metabolism. PKM2 is expressed in many human cancers and is regulated by complex mechanisms that promote tumor growth and proliferation. Therefore, it is considered an attractive therapeutic target for modulating tumor metabolism. Various stimuli allosterically regulate PKM2 by cycling it between highly active and less active states. Several small molecules activate PKM2 by binding to its intersubunit interface. Serine and cysteine serve as an activator and inhibitor of PKM2, respectively, by binding to its amino acid (AA)-binding pocket, which therefore represents a potential druggable site. Despite binding similarly to PKM2, how cysteine and serine differentially regulate this enzyme remains elusive. Using kinetic analyses, fluorescence binding, X-ray crystallography, and gel filtration experiments with asparagine, aspartate, and valine as PKM2 ligands, we examined whether the differences in the side-chain polarity of these AAs trigger distinct allosteric responses in PKM2. We found that Asn (polar) and Asp (charged) activate PKM2 and that Val (hydrophobic) inhibits it. The results also indicate that both Asn and Asp can restore the activity of Val-inhibited PKM2. AA-bound crystal structures of PKM2 displayed distinctive interactions within the binding pocket, causing unique allosteric effects in the enzyme. These structure-function analyses of AA-mediated PKM2 regulation shed light on the chemical requirements in the development of mechanism-based small-molecule modulators targeting the AA-binding pocket of PKM2 and provide broader insights into the regulatory mechanisms of complex allosteric enzymes. Full Article
sig 12-LOX catalyzes the oxidation of 2-arachidonoyl-lysolipids in platelets generating eicosanoid-lysolipids that are attenuated by iPLA2{gamma} knockout [Signal Transduction] By www.jbc.org Published On :: 2020-04-17T00:06:05-07:00 The canonical pathway of eicosanoid production in most mammalian cells is initiated by phospholipase A2-mediated release of arachidonic acid, followed by its enzymatic oxidation resulting in a vast array of eicosanoid products. However, recent work has demonstrated that the major phospholipase in mitochondria, iPLA2γ (patatin-like phospholipase domain containing 8 (PNPLA8)), possesses sn-1 specificity, with polyunsaturated fatty acids at the sn-2 position generating polyunsaturated sn-2-acyl lysophospholipids. Through strategic chemical derivatization, chiral chromatographic separation, and multistage tandem MS, here we first demonstrate that human platelet-type 12-lipoxygenase (12-LOX) can directly catalyze the regioselective and stereospecific oxidation of 2-arachidonoyl-lysophosphatidylcholine (2-AA-LPC) and 2-arachidonoyl-lysophosphatidylethanolamine (2-AA-LPE). Next, we identified these two eicosanoid-lysophospholipids in murine myocardium and in isolated platelets. Moreover, we observed robust increases in 2-AA-LPC, 2-AA-LPE, and their downstream 12-LOX oxidation products, 12(S)-HETE-LPC and 12(S)-HETE-LPE, in calcium ionophore (A23187)-stimulated murine platelets. Mechanistically, genetic ablation of iPLA2γ markedly decreased the calcium-stimulated production of 2-AA-LPC, 2-AA-LPE, and 12-HETE-lysophospholipids in mouse platelets. Importantly, a potent and selective 12-LOX inhibitor, ML355, significantly inhibited the production of 12-HETE-LPC and 12-HETE-LPE in activated platelets. Furthermore, we found that aging is accompanied by significant changes in 12-HETE-LPC in murine serum that were also markedly attenuated by iPLA2γ genetic ablation. Collectively, these results identify previously unknown iPLA2γ-initiated signaling pathways mediated by direct 12-LOX oxidation of 2-AA-LPC and 2-AA-LPE. This oxidation generates previously unrecognized eicosanoid-lysophospholipids that may serve as biomarkers for age-related diseases and could potentially be used as targets in therapeutic interventions. Full Article
sig Cross-regulation between LUBAC and caspase-1 modulates cell death and inflammation [Signal Transduction] By www.jbc.org Published On :: 2020-04-17T00:06:05-07:00 The linear ubiquitin assembly complex (LUBAC) is an essential component of the innate and adaptive immune system. Modification of cellular substrates with linear polyubiquitin chains is a key regulatory step in signal transduction that impacts cell death and inflammatory signaling downstream of various innate immunity receptors. Loss-of-function mutations in the LUBAC components HOIP and HOIL-1 yield a systemic autoinflammatory disease in humans, whereas their genetic ablation is embryonically lethal in mice. Deficiency of the LUBAC adaptor protein Sharpin results in a multi-organ inflammatory disease in mice characterized by chronic proliferative dermatitis (cpdm), which is propagated by TNFR1-induced and RIPK1-mediated keratinocyte cell death. We have previously shown that caspase-1 and -11 promoted the dermatitis pathology of cpdm mice and mediated cell death in the skin. Here, we describe a reciprocal regulation of caspase-1 and LUBAC activities in keratinocytes. We show that LUBAC interacted with caspase-1 via HOIP and modified its CARD domain with linear polyubiquitin and that depletion of HOIP or Sharpin resulted in heightened caspase-1 activation and cell death in response to inflammasome activation, unlike what is observed in macrophages. Reciprocally, caspase-1, as well as caspase-8, regulated LUBAC activity by proteolytically processing HOIP at Asp-348 and Asp-387 during the execution of cell death. HOIP processing impeded substrate ubiquitination in the NF-κB pathway and resulted in enhanced apoptosis. These results highlight a regulatory mechanism underlying efficient apoptosis in keratinocytes and provide further evidence of a cross-talk between inflammatory and cell death pathways. Full Article
sig Learning the ABCs of ATP release [Signal Transduction] By www.jbc.org Published On :: 2020-04-17T00:06:05-07:00 ATP plays important roles outside the cell, but the mechanism by which it is arrives in the extracellular environment is not clear. Dunn et al. now show that decreases in cellular cholesterol levels mediated by the ABCG1 transporter increase ATP release by volume-regulated anion channels under hypotonic conditions. Importantly, these results may imply that cells that handle cholesterol differently might experience differential extracellular ATP release during hypotonicity. Full Article
sig ABC transporters control ATP release through cholesterol-dependent volume-regulated anion channel activity [Signal Transduction] By www.jbc.org Published On :: 2020-04-17T00:06:05-07:00 Purinergic signaling by extracellular ATP regulates a variety of cellular events and is implicated in both normal physiology and pathophysiology. Several molecules have been associated with the release of ATP and other small molecules, but their precise contributions have been difficult to assess because of their complexity and heterogeneity. Here, we report on the results of a gain-of-function screen for modulators of hypotonicity-induced ATP release using HEK-293 cells and murine cerebellar granule neurons, along with bioluminescence, calcium FLIPR, and short hairpin RNA–based gene-silencing assays. This screen utilized the most extensive genome-wide ORF collection to date, covering 90% of human, nonredundant, protein-encoding genes. We identified two ABCG1 (ABC subfamily G member 1) variants, which regulate cellular cholesterol, as modulators of hypotonicity-induced ATP release. We found that cholesterol levels control volume-regulated anion channel–dependent ATP release. These findings reveal novel mechanisms for the regulation of ATP release and volume-regulated anion channel activity and provide critical links among cellular status, cholesterol, and purinergic signaling. Full Article
sig X-ray structures of catalytic intermediates of cytochrome c oxidase provide insights into its O2 activation and unidirectional proton-pump mechanisms [Molecular Biophysics] By www.jbc.org Published On :: 2020-04-24T06:08:45-07:00 Cytochrome c oxidase (CcO) reduces O2 to water, coupled with a proton-pumping process. The structure of the O2-reduction site of CcO contains two reducing equivalents, Fea32+ and CuB1+, and suggests that a peroxide-bound state (Fea33+–O−–O−–CuB2+) rather than an O2-bound state (Fea32+–O2) is the initial catalytic intermediate. Unexpectedly, however, resonance Raman spectroscopy results have shown that the initial intermediate is Fea32+–O2, whereas Fea33+–O−–O−–CuB2+ is undetectable. Based on X-ray structures of static noncatalytic CcO forms and mutation analyses for bovine CcO, a proton-pumping mechanism has been proposed. It involves a proton-conducting pathway (the H-pathway) comprising a tandem hydrogen-bond network and a water channel located between the N- and P-side surfaces. However, a system for unidirectional proton-transport has not been experimentally identified. Here, an essentially identical X-ray structure for the two catalytic intermediates (P and F) of bovine CcO was determined at 1.8 Å resolution. A 1.70 Å Fe–O distance of the ferryl center could best be described as Fea34+ = O2−, not as Fea34+–OH−. The distance suggests an ∼800-cm−1 Raman stretching band. We found an interstitial water molecule that could trigger a rapid proton-coupled electron transfer from tyrosine-OH to the slowly forming Fea33+–O−–O−–CuB2+ state, preventing its detection, consistent with the unexpected Raman results. The H-pathway structures of both intermediates indicated that during proton-pumping from the hydrogen-bond network to the P-side, a transmembrane helix closes the water channel connecting the N-side with the hydrogen-bond network, facilitating unidirectional proton-pumping during the P-to-F transition. Full Article
sig Structural insight into the recognition of pathogen-derived phosphoglycolipids by C-type lectin receptor DCAR [Protein Structure and Folding] By www.jbc.org Published On :: 2020-04-24T06:08:45-07:00 The C-type lectin receptors (CLRs) form a family of pattern recognition receptors that recognize numerous pathogens, such as bacteria and fungi, and trigger innate immune responses. The extracellular carbohydrate-recognition domain (CRD) of CLRs forms a globular structure that can coordinate a Ca2+ ion, allowing receptor interactions with sugar-containing ligands. Although well-conserved, the CRD fold can also display differences that directly affect the specificity of the receptors for their ligands. Here, we report crystal structures at 1.8–2.3 Å resolutions of the CRD of murine dendritic cell-immunoactivating receptor (DCAR, or Clec4b1), the CLR that binds phosphoglycolipids such as acylated phosphatidyl-myo-inositol mannosides (AcPIMs) of mycobacteria. Using mutagenesis analysis, we identified critical residues, Ala136 and Gln198, on the surface surrounding the ligand-binding site of DCAR, as well as an atypical Ca2+-binding motif (Glu-Pro-Ser/EPS168–170). By chemically synthesizing a water-soluble ligand analog, inositol-monophosphate dimannose (IPM2), we confirmed the direct interaction of DCAR with the polar moiety of AcPIMs by biolayer interferometry and co-crystallization approaches. We also observed a hydrophobic groove extending from the ligand-binding site that is in a suitable position to interact with the lipid portion of whole AcPIMs. These results suggest that the hydroxyl group-binding ability and hydrophobic groove of DCAR mediate its specific binding to pathogen-derived phosphoglycolipids such as mycobacterial AcPIMs. Full Article
sig Structural basis of cell-surface signaling by a conserved sigma regulator in Gram-negative bacteria [Molecular Biophysics] By www.jbc.org Published On :: 2020-04-24T06:08:45-07:00 Cell-surface signaling (CSS) in Gram-negative bacteria involves highly conserved regulatory pathways that optimize gene expression by transducing extracellular environmental signals to the cytoplasm via inner-membrane sigma regulators. The molecular details of ferric siderophore-mediated activation of the iron import machinery through a sigma regulator are unclear. Here, we present the 1.56 Å resolution structure of the periplasmic complex of the C-terminal CSS domain (CCSSD) of PupR, the sigma regulator in the Pseudomonas capeferrum pseudobactin BN7/8 transport system, and the N-terminal signaling domain (NTSD) of PupB, an outer-membrane TonB-dependent transducer. The structure revealed that the CCSSD consists of two subdomains: a juxta-membrane subdomain, which has a novel all-β-fold, followed by a secretin/TonB, short N-terminal subdomain at the C terminus of the CCSSD, a previously unobserved topological arrangement of this domain. Using affinity pulldown assays, isothermal titration calorimetry, and thermal denaturation CD spectroscopy, we show that both subdomains are required for binding the NTSD with micromolar affinity and that NTSD binding improves CCSSD stability. Our findings prompt us to present a revised model of CSS wherein the CCSSD:NTSD complex forms prior to ferric-siderophore binding. Upon siderophore binding, conformational changes in the CCSSD enable regulated intramembrane proteolysis of the sigma regulator, ultimately resulting in transcriptional regulation. Full Article
sig G{alpha}q splice variants mediate phototransduction, rhodopsin synthesis, and retinal integrity in Drosophila [Signal Transduction] By www.jbc.org Published On :: 2020-04-24T06:08:45-07:00 Heterotrimeric G proteins mediate a variety of signaling processes by coupling G protein–coupled receptors to intracellular effector molecules. In Drosophila, the Gαq gene encodes several Gαq splice variants, with the Gαq1 isoform protein playing a major role in fly phototransduction. However, Gαq1 null mutant flies still exhibit a residual light response, indicating that other Gαq splice variants or additional Gq α subunits are involved in phototransduction. Here, we isolated a mutant fly with no detectable light responses, decreased rhodopsin (Rh) levels, and rapid retinal degeneration. Using electrophysiological and genetic studies, biochemical assays, immunoblotting, real-time RT-PCR, and EM analysis, we found that mutations in the Gαq gene disrupt light responses and demonstrate that the Gαq3 isoform protein is responsible for the residual light response in Gαq1 null mutants. Moreover, we report that Gαq3 mediates rhodopsin synthesis. Depletion of all Gαq splice variants led to rapid light-dependent retinal degeneration, due to the formation stable Rh1-arrestin 2 (Arr2) complexes. Our findings clarify essential roles of several different Gαq splice variants in phototransduction and retinal integrity in Drosophila and reveal that Gαq3 functions in rhodopsin synthesis. Full Article
sig NF-{kappa}B mediates lipopolysaccharide-induced alternative pre-mRNA splicing of MyD88 in mouse macrophages [Signal Transduction] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 Although a robust inflammatory response is needed to combat infection, this response must ultimately be terminated to prevent chronic inflammation. One mechanism that terminates inflammatory signaling is the production of alternative mRNA splice forms in the Toll-like receptor (TLR) signaling pathway. Whereas most genes in the TLR pathway encode positive mediators of inflammatory signaling, several, including that encoding the MyD88 signaling adaptor, also produce alternative spliced mRNA isoforms that encode dominant-negative inhibitors of the response. Production of these negatively acting alternatively spliced isoforms is induced by stimulation with the TLR4 agonist lipopolysaccharide (LPS); thus, this alternative pre-mRNA splicing represents a negative feedback loop that terminates TLR signaling and prevents chronic inflammation. In the current study, we investigated the mechanisms regulating the LPS-induced alternative pre-mRNA splicing of the MyD88 transcript in murine macrophages. We found that 1) the induction of the alternatively spliced MyD88 form is due to alternative pre-mRNA splicing and not caused by another RNA regulatory mechanism, 2) MyD88 splicing is regulated by both the MyD88- and TRIF-dependent arms of the TLR signaling pathway, 3) MyD88 splicing is regulated by the NF-κB transcription factor, and 4) NF-κB likely regulates MyD88 alternative pre-mRNA splicing per se rather than regulating splicing indirectly by altering MyD88 transcription. We conclude that alternative splicing of MyD88 may provide a sensitive mechanism that ensures robust termination of inflammation for tissue repair and restoration of normal tissue homeostasis once an infection is controlled. Full Article
sig Biophysical characterization of SARAH domain-mediated multimerization of Hippo pathway complexes in Drosophila [Signal Transduction] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 Hippo pathway signaling limits cell growth and proliferation and maintains the stem-cell niche. These cellular events result from the coordinated activity of a core kinase cassette that is regulated, in part, by interactions involving Hippo, Salvador, and dRassF. These interactions are mediated by a conserved coiled-coil domain, termed SARAH, in each of these proteins. SARAH domain–mediated homodimerization of Hippo kinase leads to autophosphorylation and activation. Paradoxically, SARAH domain–mediated heterodimerization between Hippo and Salvador enhances Hippo kinase activity in cells, whereas complex formation with dRassF inhibits it. To better understand the mechanism by which each complex distinctly modulates Hippo kinase and pathway activity, here we biophysically characterized the entire suite of SARAH domain–mediated complexes. We purified the three SARAH domains from Drosophila melanogaster and performed an unbiased pulldown assay to identify all possible interactions, revealing that isolated SARAH domains are sufficient to recapitulate the cellular assemblies and that Hippo is a universal binding partner. Additionally, we found that the Salvador SARAH domain homodimerizes and demonstrate that this interaction is conserved in Salvador's mammalian homolog. Using native MS, we show that each of these complexes is dimeric in solution. We also measured the stability of each SARAH domain complex, finding that despite similarities at both the sequence and structural levels, SARAH domain complexes differ in stability. The identity, stoichiometry, and stability of these interactions characterized here comprehensively reveal the nature of SARAH domain–mediated complex formation and provide mechanistic insights into how SARAH domain–mediated interactions influence Hippo pathway activity. Full Article
sig Mechanistic insights explain the transforming potential of the T507K substitution in the protein-tyrosine phosphatase SHP2 [Signal Transduction] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 The protein-tyrosine phosphatase SHP2 is an allosteric enzyme critical for cellular events downstream of growth factor receptors. Mutations in the SHP2 gene have been linked to many different types of human diseases, including developmental disorders, leukemia, and solid tumors. Unlike most SHP2-activating mutations, the T507K substitution in SHP2 is unique in that it exhibits oncogenic Ras-like transforming activity. However, the biochemical basis of how the SHP2/T507K variant elicits transformation remains unclear. By combining kinetic and biophysical methods, X-ray crystallography, and molecular modeling, as well as using cell biology approaches, here we uncovered that the T507K substitution alters both SHP2 substrate specificity and its allosteric regulatory mechanism. We found that although SHP2/T507K exists in the closed, autoinhibited conformation similar to the WT enzyme, the interactions between its N-SH2 and protein-tyrosine phosphatase domains are weakened such that SHP2/T507K possesses a higher affinity for the scaffolding protein Grb2-associated binding protein 1 (Gab1). We also discovered that the T507K substitution alters the structure of the SHP2 active site, resulting in a change in SHP2 substrate preference for Sprouty1, a known negative regulator of Ras signaling and a potential tumor suppressor. Our results suggest that SHP2/T507K's shift in substrate specificity coupled with its preferential association of SHP2/T507K with Gab1 enable the mutant SHP2 to more efficiently dephosphorylate Sprouty1 at pTyr-53. This dephosphorylation hyperactivates Ras signaling, which is likely responsible for SHP2/T507K's Ras-like transforming activity. Full Article
sig NAD+ biosynthesis in bacteria is controlled by global carbon/nitrogen levels via PII signaling [Microbiology] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 NAD+ is a central metabolite participating in core metabolic redox reactions. The prokaryotic NAD synthetase enzyme NadE catalyzes the last step of NAD+ biosynthesis, converting nicotinic acid adenine dinucleotide (NaAD) to NAD+. Some members of the NadE family use l-glutamine as a nitrogen donor and are named NadEGln. Previous gene neighborhood analysis has indicated that the bacterial nadE gene is frequently clustered with the gene encoding the regulatory signal transduction protein PII, suggesting a functional relationship between these proteins in response to the nutritional status and the carbon/nitrogen ratio of the bacterial cell. Here, using affinity chromatography, bioinformatics analyses, NAD synthetase activity, and biolayer interferometry assays, we show that PII and NadEGln physically interact in vitro, that this complex relieves NadEGln negative feedback inhibition by NAD+. This mechanism is conserved in distantly related bacteria. Of note, the PII protein allosteric effector and cellular nitrogen level indicator 2-oxoglutarate (2-OG) inhibited the formation of the PII-NadEGln complex within a physiological range. These results indicate an interplay between the levels of ATP, ADP, 2-OG, PII-sensed glutamine, and NAD+, representing a metabolic hub that may balance the levels of core nitrogen and carbon metabolites. Our findings support the notion that PII proteins act as a dissociable regulatory subunit of NadEGln, thereby enabling the control of NAD+ biosynthesis according to the nutritional status of the bacterial cell. Full Article
sig Certain ortho-hydroxylated brominated ethers are promiscuous kinase inhibitors that impair neuronal signaling and neurodevelopmental processes [Cell Biology] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 The developing nervous system is remarkably sensitive to environmental signals, including disruptive toxins, such as polybrominated diphenyl ethers (PBDEs). PBDEs are an environmentally pervasive class of brominated flame retardants whose neurodevelopmental toxicity mechanisms remain largely unclear. Using dissociated cortical neurons from embryonic Rattus norvegicus, we found here that chronic exposure to 6-OH–BDE-47, one of the most prevalent hydroxylated PBDE metabolites, suppresses both spontaneous and evoked neuronal electrical activity. On the basis of our previous work on mitogen-activated protein kinase (MAPK)/extracellular signal-related kinase (ERK) (MEK) biology and our observation that 6-OH–BDE-47 is structurally similar to kinase inhibitors, we hypothesized that certain hydroxylated PBDEs mediate neurotoxicity, at least in part, by impairing the MEK–ERK axis of MAPK signal transduction. We tested this hypothesis on three experimental platforms: 1) in silico, where modeling ligand–protein docking suggested that 6-OH–BDE-47 is a promiscuous ATP-competitive kinase inhibitor; 2) in vitro in dissociated neurons, where 6-OH–BDE-47 and another specific hydroxylated BDE metabolite similarly impaired phosphorylation of MEK/ERK1/2 and activity-induced transcription of a neuronal immediate early gene; and 3) in vivo in Drosophila melanogaster, where developmental exposures to 6-OH–BDE-47 and a MAPK inhibitor resulted in offspring displaying similarly increased frequency of mushroom-body β–lobe midline crossing, a metric of axonal guidance. Taken together, our results support that certain ortho-hydroxylated PBDE metabolites are promiscuous kinase inhibitors and can cause disruptions of critical neurodevelopmental processes, including neuronal electrical activity, pre-synaptic functions, MEK–ERK signaling, and axonal guidance. Full Article
sig The mRNA levels of heat shock factor 1 are regulated by thermogenic signals via the cAMP-dependent transcription factor ATF3 [Metabolism] By www.jbc.org Published On :: 2020-05-01T00:06:09-07:00 Heat shock factor 1 (HSF1) regulates cellular adaptation to challenges such as heat shock and oxidative and proteotoxic stresses. We have recently reported a previously unappreciated role for HSF1 in the regulation of energy metabolism in fat tissues; however, whether HSF1 is differentially expressed in adipose depots and how its levels are regulated in fat tissues remain unclear. Here, we show that HSF1 levels are higher in brown and subcutaneous fat tissues than in those in the visceral depot and that HSF1 is more abundant in differentiated, thermogenic adipocytes. Gene expression experiments indicated that HSF1 is transcriptionally regulated in fat by agents that modulate cAMP levels, by cold exposure, and by pharmacological stimulation of β-adrenergic signaling. An in silico promoter analysis helped identify a putative response element for activating transcription factor 3 (ATF3) at −258 to −250 base pairs from the HSF1 transcriptional start site, and electrophoretic mobility shift and ChIP assays confirmed ATF3 binding to this sequence. Furthermore, functional assays disclosed that ATF3 is necessary and sufficient for HSF1 regulation. Detailed gene expression analysis revealed that ATF3 is one of the most highly induced ATFs in thermogenic tissues of mice exposed to cold temperatures or treated with the β-adrenergic receptor agonist CL316,243 and that its expression is induced by modulators of cAMP levels in isolated adipocytes. To the best of our knowledge, our results show for the first time that HSF1 is transcriptionally controlled by ATF3 in response to classic stimuli that promote heat generation in thermogenic tissues. Full Article
sig The focal adhesion protein kindlin-2 controls mitotic spindle assembly by inhibiting histone deacetylase 6 and maintaining {alpha}-tubulin acetylation [Signal Transduction] By www.jbc.org 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
sig Government announces Study Subsidy Scheme for Designated Professions/Sectors for 2020/21 cohort - sub-degree programmes By www.info.gov.hk Published On :: Wed, 09 Oct 2019 17:00:33 Full Article
sig Savannah College of Art and Design (Hong Kong) to discontinue operation By www.info.gov.hk Published On :: Fri, 13 Mar 2020 20:04:52 Full Article
sig Making Academic Research Accessible Can Lead to Significant Policy Change By www8.gsb.columbia.edu Published On :: Mon, 03 Feb 2020 19:52:23 +0000 Business Economics and Public Policy World Business Tuesday, February 4, 2020 - 14:45 Research from Chazen Senior Scholar Jonas Hjort shows political leaders value research findings, even willing to pay to learn results of impact evaluations Full Article
sig NJIT physics team provides novel swab design, free of charge, to augment COVID-19 testing By www.eurekalert.org Published On :: Wed, 06 May 2020 00:00:00 EDT (New Jersey Institute of Technology) A team of NJIT physicists has developed a novel test swab that can be 3D printed using inexpensive, widely available materials and speedily assembled in a range of fabrication settings. To augment the nation's testing capabilities, the inventors are making the swab's design publicly available, free of licensing fees, during the COVID-19 emergency. Full Article
sig Astronomers could spot life signs orbiting long-dead stars By www.eurekalert.org Published On :: Thu, 30 Apr 2020 00:00:00 EDT (Cornell University) To help future scientists make sense of what their telescopes are showing them, Cornell University astronomers have developed a spectral field guide for rocky worlds orbiting white dwarf stars. Full Article
sig Exoplanets: How we'll search for signs of life By www.eurekalert.org Published On :: Mon, 04 May 2020 00:00:00 EDT (Arizona State University) An interdisciplinary team of researchers, led by Arizona State University, has provided a framework called a 'detectability index' to help prioritize exoplanets to study and provide scientists with a tool to select the best targets for observation and maximize the chances of detecting life. Full Article
sig Fly ash geopolymer concrete: Significantly enhanced resistance to extreme alkali attack By www.eurekalert.org Published On :: Wed, 06 May 2020 00:00:00 EDT (University of Johannesburg) Fly ash generated by coal-fired power stations is a global environmental headache, creating groundwater and air pollution from vast landfills and ash dams. The waste product can be repurposed into geopolymer concrete, such as precast heat-cured structural elements for buildings. However, a critical durability problem has been low resistance to extreme alkali attack. UJ researchers found that high temperature heat-treatment at 200 degrees Celsius can halve this harmful mechanism in fly ash geopolymer concretes. Full Article
sig Coronavirus mutations offer insights into virus evolution By www.imperial.ac.uk Published On :: Thu, 07 May 2020 17:10:00 +0100 By analysing virus genomes from over 7,500 people infected with Covid-19, researchers have characterised patterns of diversity of SARS-CoV-2 genome. Full Article
sig Dr. Ellen Flaherty, prestigious Henderson lecturer, sets sight on key priority for us all By www.eurekalert.org Published On :: Fri, 08 May 2020 00:00:00 EDT (American Geriatrics Society) The American Geriatrics Society (AGS) today announced that Ellen Flaherty, PhD, APRN, AGSF, an assistant professor at the Dartmouth Geisel School of Medicine and director of the Dartmouth Centers for Health & Aging, will deliver the society's prestigious Henderson State-of-the-Art Lecture. Dr. Flaherty will deliver her talk, Leveraging the Potential of Interprofessional Teams in Primary Care Practice, at the AGS 2021 Annual Scientific Meeting (#AGS21) in Chicago, Ill. (May 12-15, 2021). Full Article
sig Insights From the National Diabetes Education Program National Diabetes Survey: Opportunities for Diabetes Self-Management Education and Support By spectrum.diabetesjournals.org Published On :: 2017-05-01 Linda J. PiccininoMay 1, 2017; 30:95-100From Research to Practice Full Article
sig Redesign of a Diabetes System of Care Using an All-or-None Diabetes Bundle to Build Teamwork and Improve Intermediate Outcomes By spectrum.diabetesjournals.org Published On :: 2010-07-01 Frederick J. BloomJul 1, 2010; 23:165-169From Research to Practice Full Article
sig Interview-Based Customer Insights in Developing Countries By www8.gsb.columbia.edu Published On :: Wed, 08 Jan 2020 17:00:28 +0000 What are the opportunities and challenges of collecting consumer insights in developing countries—and how can the challenges be overcome? Full Article
sig NYC Silkscreen Studio Swaps Fine Art Prints for Safety Signage By www8.gsb.columbia.edu Published On :: Wed, 22 Apr 2020 00:00:00 -0400 Gary Lichtenstein Editions has partnered with Urban Pathways to increase awareness and safety in the homeless community. Full Article