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Assessing the role of glycosphingolipids in the phenotype severity of Fabry disease mouse model [Research Articles]

Fabry disease is caused by deficient activity of α-galactosidase A, an enzyme that hydrolyzes the terminal α-galactosyl moieties from glycolipids and glycoproteins, and subsequent accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb3), globotriaosylsphingosine (lyso-Gb3), and galabiosylceramide. However, there is no known link between these compounds and disease severity. In this study, we compared Gb3 isoforms (various fatty acids) and lyso-Gb3 analogs (various sphingosine modifications) in two strains of Fabry disease mouse models: a pure C57BL/6 (B6) background or a B6/129 mixed background, with the latter exhibiting more prominent cardiac and renal hypertrophy and thermosensation deficits. Total Gb3 and lyso-Gb3 levels in the heart, kidney, and dorsal root ganglion (DRG) were similar in the two strains. However, levels of the C20-fatty acid isoform of Gb3 and particular lyso-Gb3 analogs (+18, +34) were significantly higher in Fabry-B6/129 heart tissue when compared with Fabry-B6. By contrast, there was no difference in Gb3 and lyso-Gb3 isoforms/analogs in the kidneys and DRG between the two strains. Furthermore, using immunohistochemistry, we found that Gb3 massively accumulated in DRG mechanoreceptors, a sensory neuron subpopulation with preserved function in Fabry disease. However, Gb3 accumulation was not observed in nonpeptidergic nociceptors, the disease-relevant subpopulation that has remarkably increased isolectin-B4 (the marker of nonpeptidergic nociceptors) binding and enlarged cell size. These findings suggest that specific species of Gb3 or lyso-Gb3 may play major roles in the pathogenesis of Fabry disease, and that Gb3 and lyso-Gb3 are not responsible for the pathology in all tissues or cell types.




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Characterization of essential domains in HSD17B13 for cellular localization and enzymatic activity [Research Articles]

Human genetic studies recently identified an association of SNPs in the 17-β hydroxysteroid dehydrogenase 13 (HSD17B13) gene with alcoholic and nonalcoholic fatty liver disease development. Mutant HSD17B13 variants devoid of enzymatic function have been demonstrated to be protective from cirrhosis and liver cancer, supporting the development of HSD17B13 as a promising therapeutic target. Previous studies have demonstrated that HSD17B13 is a lipid droplet (LD)-associated protein. However, the critical domains that drive LD targeting or determine the enzymatic activity have yet to be defined. Here we used mutagenesis to generate multiple truncated and point-mutated proteins and were able to demonstrate in vitro that the N-terminal hydrophobic domain, PAT-like domain, and a putative α-helix/β-sheet/α-helix domain in HSD17B13 are all critical for LD targeting. Similarly, we characterized the predicted catalytic, substrate-binding, and homodimer interaction sites and found them to be essential for the enzymatic activity of HSD17B13, in addition to our previous identification of amino acid P260 and cofactor binding site. In conclusion, we identified critical domains and amino acid sites that are essential for the LD localization and protein function of HSD17B13, which may facilitate understanding of its function and targeting of this protein to treat chronic liver diseases.




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Bioavailability and spatial distribution of fatty acids in the rat retina after dietary omega-3 supplementation [Research Articles]

Spatial changes of FAs in the retina in response to different dietary n-3 formulations have never been explored, although a diet rich in EPA and DHA is recommended to protect the retina against the effects of aging. In this study, Wistar rats were fed for 8 weeks with balanced diet including either EPA-containing phospholipids (PLs), EPA-containing TGs, DHA-containing PLs, or DHA-containing TGs. Qualitative changes in FA composition of plasma, erythrocytes, and retina were evaluated by gas chromatography-flame ionization detector. Following the different dietary intakes, changes to the quantity and spatial organization of PC and PE species in retina were determined by LC coupled to MS/MS and MALDI coupled to MS imaging. The omega-3 content in the lipids of plasma and erythrocytes suggests that PLs as well as TGs are good omega-3 carriers for retina. However, a significant increase in DHA content in retina was observed, especially molecular species as di-DHA-containing PC and PE, as well as an increase in very long chain PUFAs (more than 28 carbons) following PL-EPA and TG-DHA diets only. All supplemented diets triggered spatial organization changes of DHA in the photoreceptor layer around the optic nerve. Taken together, these findings suggest that dietary omega-3 supplementation can modify the content of FAs in the rat retina.




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Nuclear translocation ability of Lipin differentially affects gene expression and survival in fed and fasting Drosophila [Research Articles]

Lipins are eukaryotic proteins with functions in lipid synthesis and the homeostatic control of energy balance. They execute these functions by acting as phosphatidate phosphatase enzymes in the cytoplasm and by changing gene expression after translocation into the cell nucleus, in particular under fasting conditions. Here, we asked whether nuclear translocation and the enzymatic activity of Drosophila Lipin serve essential functions and how gene expression changes, under both fed and fasting conditions, when nuclear translocation is impaired. To address these questions, we created a Lipin null mutant, a mutant expressing Lipin lacking a nuclear localization signal (LipinNLS), and a mutant expressing enzymatically dead Lipin. Our data support the conclusion that the enzymatic but not nuclear gene regulatory activity of Lipin is essential for survival. Notably, adult LipinNLS flies were not only viable but also exhibited improved life expectancy. In contrast, they were highly susceptible to starvation. Both the improved life expectancy in the fed state and the decreased survival in the fasting state correlated with changes in metabolic gene expression. Moreover, increased life expectancy of fed flies was associated with a decreased metabolic rate. Interestingly, in addition to metabolic genes, genes involved in feeding behavior and the immune response were misregulated in LipinNLS flies. Altogether, our data suggest that the nuclear activity of Lipin influences the genomic response to nutrient availability with effects on life expectancy and starvation resistance. Thus, nutritional or therapeutic approaches that aim at lowering nuclear translocation of lipins in humans may be worth exploring.




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High resolution structure of human apolipoprotein (a) kringle IV type 2: beyond the lysine binding site [Research Articles]

Lipoprotein (a) [Lp(a)] is characterized by an LDL-like composition in terms of lipids and apoB100, and by one copy of a unique glycoprotein, apo(a). The apo(a) structure is mainly based on the repetition of tandem kringle domains with high homology to plasminogen kringles 4 and 5. Among them, kringle IV type 2 (KIV-2) is present in a highly variable number of genetically encoded repeats, whose length is inversely related to Lp(a) plasma concentration and cardiovascular risk. Despite it being the major component of apo(a), the actual function of KIV-2 is still unclear. Here, we describe the first high-resolution crystallographic structure of this domain. It shows a general fold very similar to other KIV domains with high and intermediate affinity for the lysine analog, -aminocaproic acid. Interestingly, KIV-2 presents a lysine binding site (LBS) with a unique shape and charge distribution. KIV-2 affinity for predicted small molecule binders was found to be negligible in surface plasmon resonance experiments; and with the LBS being nonfunctional, we propose to rename it "pseudo-LBS". Further investigation of the protein by computational small-molecule docking allowed us to identify a possible heparin-binding site away from the LBS, which was confirmed by specific reverse charge mutations abolishing heparin binding. This study opens new possibilities to define the pathogenesis of Lp(a)-related diseases and to facilitate the design of specific therapeutic drugs.




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The anti-tubercular activity of simvastatin is mediated by cholesterol-driven autophagy via the AMPK-mTORC1-TFEB axis [Research Articles]

The rise of drug-resistant tuberculosis poses a major risk to public health. Statins, which inhibit both cholesterol biosynthesis and protein prenylation branches of the mevalonate pathway, increase anti-tubercular antibiotic efficacy in animal models. However, the underlying molecular mechanisms are unknown. In this study, we used an in vitro macrophage infection model to investigate simvastatin’s anti-tubercular activity by systematically inhibiting each branch of the mevalonate pathway and evaluating the effects of the branch-specific inhibitors on mycobacterial growth. The anti-tubercular activity of simvastatin used at clinically relevant doses specifically targeted the cholesterol biosynthetic branch rather than the prenylation branches of the mevalonate pathway. Using Western blot analysis and AMP/ATP measurements, we found that simvastatin treatment blocked activation of mechanistic target of rapamycin complex 1 (mTORC1), activated AMP-activated protein kinase (AMPK) through increased intracellular AMP:ATP ratios, and favored nuclear translocation of transcription factor EB (TFEB). These mechanisms all induce autophagy, which is anti-mycobacterial. The biological effects of simvastatin on the AMPK-mTORC1-TFEB-autophagy axis were reversed by adding exogenous cholesterol to the cells. Our data demonstrate that the anti-tubercular activity of simvastatin requires inhibiting cholesterol biosynthesis, reveal novel links between cholesterol homeostasis, the AMPK-mTORC1-TFEB axis, and Mycobacterium tuberculosis infection control, and uncover new anti-tubercular therapy targets.




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Stimulation of ABCB4/MDR3 ATPase activity requires an intact phosphatidylcholine lipid [Research Articles]

ABCB4/MDR3 is located in the canalicular membrane of hepatocytes and translocates PC-lipids from the cytoplasmic to the extracellular leaflet. ABCB4 is an ATP-dependent transporter that reduces the harsh detergent effect of the bile salts by counteracting self-digestion. To do so, ABCB4 provides PC lipids for extraction into bile. PC lipids account for 40% of the entire pool of lipids in the canalicular membrane with an unknown distribution over both leaflets. Extracted PC lipids end up in so-called mixed micelles. Mixed micelles are composed of phospholipids, bile salts, and cholesterol. Ninety to ninety-five percent of the phospholipids are members of the PC family, but only a subset of mainly 16.0-18:1 PC and 16:0-18:2 PC variants are present. To elucidate whether ABCB4 is the key discriminator in this enrichment of specific PC lipids, we used in vitro studies to identify crucial determinants in substrate selection. We demonstrate that PC-lipid moieties alone are insufficient for stimulating ABCB4 ATPase activity, and that at least two acyl chains and the backbone itself are required for a productive interaction. The nature of the fatty acids, like length or saturation has a quantitative impact on the ATPase activity. Our data demonstrate a two-step enrichment and protective function of ABCB4 to mitigate the harsh detergent effect of the bile salts, because ABCB4 can translocate more than just the PC-lipid variants found in bile.




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Site-specific deacylation by ABHD17a controls BK channel splice variant activity [Signal Transduction]

S-Acylation, the reversible post-translational lipid modification of proteins, is an important mechanism to control the properties and function of ion channels and other polytopic transmembrane proteins. However, although increasing evidence reveals the role of diverse acyl protein transferases (zDHHC) in controlling ion channel S-acylation, the acyl protein thioesterases that control ion channel deacylation are very poorly defined. Here we show that ABHD17a (α/β-hydrolase domain-containing protein 17a) deacylates the stress-regulated exon domain of large conductance voltage- and calcium-activated potassium (BK) channels inhibiting channel activity independently of effects on channel surface expression. Importantly, ABHD17a deacylates BK channels in a site-specific manner because it has no effect on the S-acylated S0–S1 domain conserved in all BK channels that controls membrane trafficking and is deacylated by the acyl protein thioesterase Lypla1. Thus, distinct S-acylated domains in the same polytopic transmembrane protein can be regulated by different acyl protein thioesterases revealing mechanisms for generating both specificity and diversity for these important enzymes to control the properties and functions of ion channels.




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Functional impact of a congenital stationary night blindness type 2 mutation depends on subunit composition of Cav1.4 Ca2+ channels [Neurobiology]

Voltage-gated Cav1 and Cav2 Ca2+ channels are comprised of a pore-forming α1 subunit (Cav1.1-1.4, Cav2.1-2.3) and auxiliary β (β1-4) and α2δ (α2δ−1−4) subunits. The properties of these channels vary with distinct combinations of Cav subunits and alternative splicing of the encoding transcripts. Therefore, the impact of disease-causing mutations affecting these channels may depend on the identities of Cav subunits and splice variants. Here, we analyzed the effects of a congenital stationary night blindness type 2 (CSNB2)-causing mutation, I745T (IT), in Cav1.4 channels typical of those in human retina: Cav1.4 splice variants with or without exon 47 (Cav1.4+ex47 and Cav1.4Δex47, respectively), and the auxiliary subunits, β2X13 and α2δ-4. We find that IT caused both Cav1.4 splice variants to activate at significantly more negative voltages and with slower deactivation kinetics than the corresponding WT channels. These effects of the IT mutation, along with unexpected alterations in ion selectivity, were generally larger in channels lacking exon 47. The weaker ion selectivity caused by IT led to hyperpolarizing shifts in the reversal potential and large outward currents that were evident in channels containing the auxiliary subunits β2X13 and α2δ-4 but not in those with β2A and α2δ-1. We conclude that the IT mutation stabilizes channel opening and alters ion selectivity of Cav1.4 in a manner that is strengthened by exclusion of exon 47 and inclusion of β2X13 and α2δ-4. Our results reveal complex actions of IT in modifying the properties of Cav1.4 channels, which may influence the pathological consequences of this mutation in retinal photoreceptors.




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Solvent accessibility changes in a Na+-dependent C4-dicarboxylate transporter suggest differential substrate effects in a multistep mechanism [Membrane Biology]

The divalent anion sodium symporter (DASS) family (SLC13) plays critical roles in metabolic homeostasis, influencing many processes, including fatty acid synthesis, insulin resistance, and adiposity. DASS transporters catalyze the Na+-driven concentrative uptake of Krebs cycle intermediates and sulfate into cells; disrupting their function can protect against age-related metabolic diseases and can extend lifespan. An inward-facing crystal structure and an outward-facing model of a bacterial DASS family member, VcINDY from Vibrio cholerae, predict an elevator-like transport mechanism involving a large rigid body movement of the substrate-binding site. How substrate binding influences the conformational state of VcINDY is currently unknown. Here, we probe the interaction between substrate binding and protein conformation by monitoring substrate-induced solvent accessibility changes of broadly distributed positions in VcINDY using a site-specific alkylation strategy. Our findings reveal that accessibility to all positions tested is modulated by the presence of substrates, with the majority becoming less accessible in the presence of saturating concentrations of both Na+ and succinate. We also observe separable effects of Na+ and succinate binding at several positions suggesting distinct effects of the two substrates. Furthermore, accessibility changes to a solely succinate-sensitive position suggests that substrate binding is a low-affinity, ordered process. Mapping these accessibility changes onto the structures of VcINDY suggests that Na+ binding drives the transporter into an as-yet-unidentified conformational state, involving rearrangement of the substrate-binding site–associated re-entrant hairpin loops. These findings provide insight into the mechanism of VcINDY, which is currently the only structurally characterized representative of the entire DASS family.




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Exofacial membrane composition and lipid metabolism regulates plasma membrane P4-ATPase substrate specificity [Lipids]

The plasma membrane of a cell is characterized by an asymmetric distribution of lipid species across the exofacial and cytofacial aspects of the bilayer. Regulation of membrane asymmetry is a fundamental characteristic of membrane biology and is crucial for signal transduction, vesicle transport, and cell division. The type IV family of P-ATPases, or P4-ATPases, establishes membrane asymmetry by selection and transfer of a subset of membrane lipids from the lumenal or exofacial leaflet to the cytofacial aspect of the bilayer. It is unclear how P4-ATPases sort through the spectrum of membrane lipids to identify their desired substrate(s) and how the membrane environment modulates this activity. Therefore, we tested how the yeast plasma membrane P4-ATPase, Dnf2, responds to changes in membrane composition induced by perturbation of endogenous lipid biosynthetic pathways or exogenous application of lipid. The primary substrates of Dnf2 are glucosylceramide (GlcCer) and phosphatidylcholine (PC, or their lyso-lipid derivatives), and we find that these substrates compete with each other for transport. Acutely inhibiting sphingolipid synthesis using myriocin attenuates transport of exogenously applied GlcCer without perturbing PC transport. Deletion of genes controlling later steps of glycosphingolipid production also perturb GlcCer transport to a greater extent than PC transport. In contrast, perturbation of ergosterol biosynthesis reduces PC and GlcCer transport equivalently. Surprisingly, application of lipids that are poor transport substrates differentially affects PC and GlcCer transport by Dnf2, thus altering substrate preference. Our data indicate that Dnf2 exhibits exquisite sensitivity to the membrane composition, thus providing feedback onto the function of the P4-ATPases.




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Accurate MS-based Rab10 Phosphorylation Stoichiometry Determination as Readout for LRRK2 Activity in Parkinson's Disease [Research]

Pathogenic mutations in the Leucine-rich repeat kinase 2 (LRRK2) are the predominant genetic cause of Parkinson's disease (PD). They increase its activity, resulting in augmented Rab10-Thr73 phosphorylation and conversely, LRRK2 inhibition decreases pRab10 levels. Currently, there is no assay to quantify pRab10 levels for drug target engagement or patient stratification. To meet this challenge, we developed an high accuracy and sensitivity targeted mass spectrometry (MS)-based assay for determining Rab10-Thr73 phosphorylation stoichiometry in human samples. It uses synthetic stable isotope-labeled (SIL) analogues for both phosphorylated and nonphosphorylated tryptic peptides surrounding Rab10-Thr73 to directly derive the percentage of Rab10 phosphorylation from attomole amounts of the endogenous phosphopeptide. The SIL and the endogenous phosphopeptides are separately admitted into an Orbitrap analyzer with the appropriate injection times. We test the reproducibility of our assay by determining Rab10-Thr73 phosphorylation stoichiometry in neutrophils of LRRK2 mutation carriers before and after LRRK2 inhibition. Compared with healthy controls, the PD predisposing mutation carriers LRRK2 G2019S and VPS35 D620N display 1.9-fold and 3.7-fold increased pRab10 levels, respectively. Our generic MS-based assay further establishes the relevance of pRab10 as a prognostic PD marker and is a powerful tool for determining LRRK2 inhibitor efficacy and for stratifying PD patients for LRRK2 inhibitor treatment.




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Measuring Site-specific Glycosylation Similarity between Influenza a Virus Variants with Statistical Certainty [Research]

Influenza A virus (IAV) mutates rapidly, resulting in antigenic drift and poor year-to-year vaccine effectiveness. One challenge in designing effective vaccines is that genetic mutations frequently cause amino acid variations in IAV envelope protein hemagglutinin (HA) that create new N-glycosylation sequons; resulting N-glycans cause antigenic shielding, allowing viral escape from adaptive immune responses. Vaccine candidate strain selection currently involves correlating antigenicity with HA protein sequence among circulating strains, but quantitative comparison of site-specific glycosylation information may likely improve the ability to design vaccines with broader effectiveness against evolving strains. However, there is poor understanding of the influence of glycosylation on immunodominance, antigenicity, and immunogenicity of HA, and there are no well-tested methods for comparing glycosylation similarity among virus samples. Here, we present a method for statistically rigorous quantification of similarity between two related virus strains that considers the presence and abundance of glycopeptide glycoforms. We demonstrate the strength of our approach by determining that there was a quantifiable difference in glycosylation at the protein level between WT IAV HA from A/Switzerland/9715293/2013 (SWZ13) and a mutant strain of SWZ13, even though no N-glycosylation sequons were changed. We determined site-specifically that WT and mutant HA have varying similarity at the glycosylation sites of the head domain, reflecting competing pressures to evade host immune response while retaining viral fitness. To our knowledge, our results are the first to quantify changes in glycosylation state that occur in related proteins of considerable glycan heterogeneity. Our results provide a method for understanding how changes in glycosylation state are correlated with variations in protein sequence, which is necessary for improving IAV vaccine strain selection. Understanding glycosylation will be especially important as we find new expression vectors for vaccine production, as glycosylation state depends greatly on the host species.




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Glutathionylation Decreases Methyltransferase Activity of PRMT5 and Inhibits Cell Proliferation [Research]

Glutathionylation is an important posttranslational modification that protects proteins from further oxidative damage as well as influencing protein structure and activity. In the present study, we demonstrate that the cysteine-42 residue in protein arginine N-methyltransferase 5 (PRMT5) is glutathionylated in aged mice or in cells that have been exposed to oxidative stress. Deglutathionylation of this protein is catalyzed by glutaredoxin-1 (Grx1). Using mutagenesis and subsequent biochemical analyses, we show that glutathionylation decreased the binding affinity of PRMT5 with methylosome protein-50 (MEP50) and reduced the methyltransferase activity of PRMT5. Furthermore, overexpression of PRMT5-C42A mutant caused a significant increase in histone methylation in HEK293T and A549 cells and promoted cell growth, whereas overexpression of the PRMT5-C42D mutant, a mimic of glutathionylated PRMT5, inhibited cell proliferation. Taken together, our results demonstrate a new mechanism of regulation of PRMT5 methyltransferases activity and suggest that PRMT5 glutathionylation is partly responsible for reactive oxygen species-mediated cell growth inhibition.




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Sialylation of Asparagine 612 Inhibits Aconitase Activity during Mouse Sperm Capacitation; a Possible Mechanism for the Switch from Oxidative Phosphorylation to Glycolysis [Research]

After ejaculation, mammalian spermatozoa must undergo a process known as capacitation in order to successfully fertilize the oocyte. Several post-translational modifications occur during capacitation, including sialylation, which despite being limited to a few proteins, seems to be essential for proper sperm-oocyte interaction. Regardless of its importance, to date, no single study has ever identified nor quantified which glycoproteins bearing terminal sialic acid (Sia) are altered during capacitation. Here we characterize sialylation during mouse sperm capacitation. Using tandem MS coupled with liquid chromatography (LC–MS/MS), we found 142 nonreductant peptides, with 9 of them showing potential modifications on their sialylated oligosaccharides during capacitation. As such, N-linked sialoglycopeptides from C4b-binding protein, endothelial lipase (EL), serine proteases 39 and 52, testis-expressed protein 101 and zonadhesin were reduced following capacitation. In contrast, mitochondrial aconitate hydratase (aconitase; ACO2), a TCA cycle enzyme, was the only protein to show an increase in Sia content during capacitation. Interestingly, although the loss of Sia within EL (N62) was accompanied by a reduction in its phospholipase A1 activity, a decrease in the activity of ACO2 (i.e. stereospecific isomerization of citrate to isocitrate) occurred when sialylation increased (N612). The latter was confirmed by N612D recombinant protein tagged with both His and GFP. The replacement of Sia for the negatively charged Aspartic acid in the N612D mutant caused complete loss of aconitase activity compared with the WT. Computer modeling show that N612 sits atop the catalytic site of ACO2. The introduction of Sia causes a large conformational change in the alpha helix, essentially, distorting the active site, leading to complete loss of function. These findings suggest that the switch from oxidative phosphorylation, over to glycolysis that occurs during capacitation may come about through sialylation of ACO2.




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Spatially Resolved Activity-based Proteomic Profiles of the Murine Small Intestinal Lipases [Research]

Despite the crucial function of the small intestine in nutrient uptake our understanding of the molecular events underlying the digestive function is still rudimentary. Recent studies demonstrated that enterocytes do not direct the entire dietary triacylglycerol toward immediate chylomicron synthesis. Especially after high-fat challenges, parts of the resynthesized triacylglycerol are packaged into cytosolic lipid droplets for transient storage in the endothelial layer of the small intestine. The reason for this temporary storage of triacylglycerol is not completely understood. To utilize lipids from cytosolic lipid droplets for chylomicron synthesis in the endoplasmic reticulum, stored triacylglycerol has to be hydrolyzed either by cytosolic lipolysis or lipophagy. Interestingly, triacylglycerol storage and chylomicron secretion rates are unevenly distributed along the small intestine, with the proximal jejunum exhibiting the highest intermittent storage capacity. We hypothesize that correlating hydrolytic enzyme activities with the reported distribution of triacylglycerol storage and chylomicron secretion in different sections of the small intestine is a promising strategy to determine key enzymes in triacylglycerol remobilization. We employed a serine hydrolase specific activity-based labeling approach in combination with quantitative proteomics to identify and rank hydrolases based on their relative activity in 11 sections of the small intestine. Moreover, we identified several clusters of enzymes showing similar activity distribution along the small intestine. Merging our activity-based results with substrate specificity and subcellular localization known from previous studies, carboxylesterase 2e and arylacetamide deacetylase emerge as promising candidates for triacylglycerol mobilization from cytosolic lipid droplets in enterocytes.




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The Beauty of Proteomics [Invited]

Cover art by Julie Newdoll for MCP April issue.




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Quantitative profiling of protein tyrosine kinases in human cancer cell lines by multiplexed parallel reaction monitoring assays [Technology]

Protein tyrosine kinases (PTKs) play key roles in cellular signal transduction, cell cycle regulation, cell division, and cell differentiation. Dysregulation of PTK-activated pathways, often by receptor overexpression, gene amplification, or genetic mutation, is a causal factor underlying numerous cancers. In this study, we have developed a parallel reaction monitoring (PRM)-based assay for quantitative profiling of 83 PTKs. The assay detects 308 proteotypic peptides from 54 receptor tyrosine kinases and 29 nonreceptor tyrosine kinases in a single run. Quantitative comparisons were based on the labeled reference peptide method. We implemented the assay in four cell models: 1) a comparison of proliferating versus epidermal growth factor (EGF)-stimulated A431 cells, 2) a comparison of SW480Null (mutant APC) and SW480APC (APC restored) colon tumor cell lines, and 3) a comparison of 10 colorectal cancer cell lines with different genomic abnormalities, and 4) lung cancer cell lines with either susceptibility (11-18) or acquired resistance (11-18R) to the epidermal growth factor receptor tyrosine kinase inhibitor erlotinib. We observed distinct PTK expression changes that were induced by stimuli, genomic features or drug resistance, which were consistent with previous reports. However, most of the measured expression differences were novel observations. For example, acquired resistance to erlotinib in the 11-18 cell model was associated not only with previously reported upregulation of MET, but also with upregulation of FLK2 and downregulation of LYN and PTK7. Immunoblot analyses and shotgun proteomics data were highly consistent with PRM data. Multiplexed PRM assays provide a targeted, systems-level profiling approach to evaluate cancer-related proteotypes and adaptations. Data are available through Proteome eXchange Accession PXD002706.




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Meta-heterogeneity: evaluating and describing the diversity in glycosylation between sites on the same glycoprotein [Review]

Mass spectrometry-based glycoproteomics has gone through some incredible developments over the last few years. Technological advances in glycopeptide enrichment, fragmentation methods, and data analysis workflows have enabled the transition of glycoproteomics from a niche application, mainly focused on the characterization of isolated glycoproteins, to a mature technology capable of profiling thousands of intact glycopeptides at once. In addition to numerous biological discoveries catalyzed by the technology, we are also observing an increase in studies focusing on global protein glycosylation and the relationship between multiple glycosylation sites on the same protein. It has become apparent that just describing protein glycosylation in terms of micro- and macro-heterogeneity, respectively the variation and occupancy of glycans at a given site, is not sufficient to describe the observed interactions between sites. In this perspective we propose a new term, meta-heterogeneity, to describe a higher level of glycan regulation: the variation in glycosylation across multiple sites of a given protein. We provide literature examples of extensive meta-heterogeneity on relevant proteins such as antibodies, erythropoietin, myeloperoxidase and a number of serum and plasma proteins. Furthermore, we postulate on the possible biological reasons and causes behind the intriguing meta-heterogeneity observed in glycoproteins.




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Methods for Enrichment and Assignment of N-Acetylglucosamine Modification Sites [Review]

O-GlcNAcylation, the addition of a single N-acetylglucosamine residue to serine and threonine residues of cytoplasmic, nuclear, or mitochondrial proteins, is a widespread regulatory post-translational modification. It is involved in response to nutritional status and stress and its dysregulation is associated with diseases ranging from Alzheimer’s to diabetes.  While the modification was first detected over thirty-five years ago, research into the function of O-GlcNAcylation has accelerated dramatically in the last ten years due to the development of new enrichment and mass spectrometry techniques that facilitate its analysis.  This article summarizes methods for O-GlcNAc enrichment, key mass spectrometry instrumentation advancements, particularly those that allow modification site localization, and software tools that allow analysis of data from O-GlcNAc modified peptides.




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Blockade of High-Fat Diet Proteomic Phenotypes using Exercise as Prevention or Treatment [Technological Innovation and Resources]

The increasing consumption of high-fat foods combined with a lack of exercise is a major contributor to the burden of obesity in humans. Aerobic exercise such as running is known to provide metabolic benefits, but how the over-consumption of a high fat diet (HFD) and exercise interact is not well characterized at the molecular level. Here, we examined the plasma proteome in mice for the effects of aerobic exercise as both a treatment and as a preventative regime for animals on either HFD or a healthy control diet. This analysis detected large changes in the plasma proteome induced by the HFD, such as increased abundance of SERPINA7, ALDOB, and down-regulation of SERPINA1E, CFD (adipsin). Some of these changes were significantly reverted using exercise as a preventative measure, but not as a treatment regime. To determine if either the intensity, or duration, of exercise influenced the outcome, we compared high-intensity interval training (HIIT) and endurance running. Endurance running slightly out-performed HIIT exercise, but overall, both provided similar reversion in abundance of plasma proteins modulated by the high-fat diet including SERPINA7, APOE, SERPINA1E, and CFD. Finally, we compared the changes induced by over-consumption of HFD to previous data from mice fed an isocaloric high saturated fat (SFA) or polyunsaturated fat (PUFA) diet. This identified several common changes including increased APOC2 and APOE, but also highlighted changes specific for either over-consumption of HFD (ALDOB, SERPINA7, CFD), SFA-based diets (SERPINA1E), or PUFA-based diets (Haptoglobin - Hp). Together, these data highlight the importance of early intervention with exercise to revert HFD-induced phenotypes and suggest some of the molecular mechanisms leading to the changes in the plasma proteome generated by high fat diet consumption. Web-based interactive visualizations are provided for this dataset (larancelab.com/hfd-exercise), which give insight into diet and exercise phenotypic interactions on the plasma proteome.




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The complexity and dynamics of the tissue glycoproteome associated with prostate cancer progression [Research]

The complexity and dynamics of the immensely heterogeneous glycoproteome of the prostate cancer (PCa) tumour micro-environment remain incompletely mapped, a knowledge gap that impedes our molecular-level understanding of the disease. To this end, we have used sensitive glycomics and glycoproteomics to map the protein-, cell- and tumour grade-specific N- and O-glycosylation in surgically-removed PCa tissues spanning five histological grades (n = 10/grade) and tissues from patients with benign prostatic hyperplasia (n = 5). Quantitative glycomics revealed PCa grade-specific alterations of the oligomannosidic-, paucimannosidic- and branched sialylated complex-type N-glycans, and dynamic remodelling of the sialylated core 1- and core 2-type O-glycome. Deep quantitative glycoproteomics identified ~7,400 unique N-glycopeptides from 500 N-glycoproteins and ~500 unique O-glycopeptides from nearly 200 O-glycoproteins. With reference to a recent Tissue and Blood Atlas, our data indicate that paucimannosidic glycans of the PCa tissues arise mainly from immune cell-derived glycoproteins. Further, the grade-specific PCa glycosylation arises primarily from dynamics in the cellular makeup of the PCa tumour microenvironment across grades involving increased oligomannosylation of prostate-derived glycoproteins and decreased bisecting GlcNAcylation of N-glycans carried by the extracellular matrix proteins. Further, elevated expression of several oligosaccharyltransferase subunits and enhanced N-glycoprotein site occupancy were observed associated with PCa progression. Finally, correlations between the protein-specific glycosylation and PCa progression were observed including increased site-specific core 2-type O-glycosylation of collagen VI. In conclusion, integrated glycomics and glycoproteomics have enabled new insight into the complexity and dynamics of the tissue glycoproteome associated with PCa progression generating an important resource to explore the underpinning disease mechanisms.




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Isolation of acetylated and unmodified protein N-terminal peptides by strong cation exchange chromatographic separation of TrypN-digested peptides [Technological Innovation and Resources]

We developed a simple and rapid method to enrich protein N-terminal peptides, in which the protease TrypN is first employed to generate protein N-terminal peptides without Lys or Arg and internal peptides with two positive charges at their N-termini, and then the N-terminal peptides with or without N-acetylation are separated from the internal peptides by strong cation exchange chromatography according to a retention model based on the charge/orientation of peptides. This approach was applied to 20 μg of human HEK293T cell lysate proteins to profile the N-terminal proteome. On average, 1,550 acetylated and 200 unmodified protein N-terminal peptides were successfully identified in a single LC/MS/MS run with less than 3% contamination with internal peptides, even when we accepted only canonical protein N-termini registered in the Swiss-Prot database. Since this method involves only two steps, protein digestion and chromatographic separation, without the need for tedious chemical reactions, it should be useful for comprehensive profiling of protein N-termini, including proteoforms with neo-N-termini.




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Proteomic analyses identify differentially expressed proteins and pathways between low-risk and high-risk subtypes of early-stage lung adenocarcinoma and their prognostic impacts [Research]

The histopathological subtype of lung adenocarcinoma (LUAD) is closely associated with prognosis. Micropapillary or solid predominant LUAD tends to relapse after surgery at an early stage, whereas lepidic pattern shows a favorable outcome. However, the molecular mechanism underlying this phenomenon remains unknown. Here, we recruited 31 lepidic predominant LUADs (LR: low-risk subtype group) and 28 micropapillary or solid predominant LUADs (HR: high-risk subtype group). Tissues of these cases were obtained and label-free quantitative proteomic and bioinformatic analyses were performed. Additionally, prognostic impact of targeted proteins was validated using The Cancer Genome Atlas databases (n=492) and tissue microarrays composed of early-stage LUADs (n=228). A total of 192 differentially expressed proteins were identified between tumor tissues of LR and HR and three clusters were identified via hierarchical clustering excluding eight proteins. Cluster 1 (65 proteins) showed a sequential decrease in expression from normal tissues to tumor tissues of LR and then to HR and was predominantly enriched in pathways such as tyrosine metabolism and ECM-receptor interaction, and increased matched mRNA expression of 18 proteins from this cluster predicted favorable prognosis. Cluster 2 (70 proteins) demonstrated a sequential increase in expression from normal tissues to tumor tissues of LR and then to HR and was mainly enriched in pathways such as extracellular organization, DNA replication and cell cycle, and high matched mRNA expression of 25 proteins indicated poor prognosis. Cluster 3 (49 proteins) showed high expression only in LR, with high matched mRNA expression of 20 proteins in this cluster indicating favorable prognosis. Furthermore, high expression of ERO1A and FEN1 at protein level predicted poor prognosis in early-stage LUAD, supporting the mRNA results. In conclusion, we discovered key differentially expressed proteins and pathways between low-risk and high-risk subtypes of early-stage LUAD. Some of these proteins could serve as potential biomarkers in prognostic evaluation.




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Global lysine acetylation and 2-hydroxyisobutyrylation reveal the metabolism conversion mechanism in Giardia lamblia [Research]

Giardia lamblia (G. lamblia) disease is a zoonosis with a-infection rate affecting the general population of the world. Despite the constant possibility of damage due to their own metabolism, G. lamblia have survived and evolved to adapt to various environments. However, research on energy-metabolism conversion in G. lamblia is limited. This study aimed to reveal the dynamic metabolism-conversion mechanism in G. lamblia under sugar starvation by detecting global lysine acetylation and 2-hydroxyisobutyrylation sites combined with quantitative proteome analyses. A total of 2999 acetylation sites on 956 proteins and 8877 2-hydroxyisobutyryl sites on 1546 proteins were quantified under sugar starvation. Integrated Kac and Khib data revealed that modified proteins were associated with arginine biosynthesis, glycolysis/gluconeogenesis, and alanine, aspartate, and glutamate metabolism. These findings suggested that lysine acetylation and 2-hydroxyisobutyrylation were ubiquitous and provided deep insight into the metabolism-conversion mechanism in G. lamblia under sugar starvation. Overall, these results can help understand the biology of G. lamblia infections and reveal the evolution rule from prokaryote to eukaryote.




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The Role of Sub-state and Non-state Actors in International Climate Processes: Civil Society

The Role of Sub-state and Non-state Actors in International Climate Processes: Civil Society Research paper sysadmin 27 November 2018

Given today’s challenging geopolitical conditions and the evolving nature of the international climate regime since Paris, civil society must now once again recalibrate its strategies to ensure continued and increasing relevance.

Photo by The Climate Reality Project, ‘People’s Climate March Protest’, via Unsplash, 2017.

This is one of four background papers feeding into a synthesis paper entitled The Role of Sub-state and Non-state Actors in International Climate Processes.

Summary

  • Following the failure of the 15th Conference of the Parties (COP 15) in Copenhagen in 2009, there was a step change in the sophistication and unity of civil society engagement on climate policy. This ensured that, subsequently, civil society was more effective in exercising multiple channels of influence around the negotiations for the Paris Agreement in 2015.
  • Civil society proved to be particularly effective at harnessing the twin narratives of climate science and economics, and at leveraging an emerging multi-level governance architecture, to create political space for climate leadership.
  • Given today’s challenging geopolitical conditions and the evolving nature of the international climate regime since Paris, civil society must now once again recalibrate its strategies to ensure continued and increasing relevance.
  • In particular, the shift to a more ‘nationally grounded’ implementation regime focusing on individual states’ climate commitments will require civil society to become more effective at influencing domestic politics. At the same time, civil society will need to continue to seek strategic synergies at the international level.
  • Civil society has a central role to play in ensuring that the first key test of the Paris ‘ratchet’ mechanism – revising countries’ pledged climate actions, or Nationally Determined Contributions (NDCs), by 2020 – is robust, science-informed and strongly rooted in domestic politics.




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Proportionality in the Conduct of Hostilities: The Incidental Harm Side of the Assessment

Proportionality in the Conduct of Hostilities: The Incidental Harm Side of the Assessment Research paper sysadmin 6 December 2018

Clarification of international humanitarian law is important in ensuring compliance with the rule of proportionality, but a culture of compliance within armed forces and groups is also crucial.

Members of civil right defence conduct a search and rescue operation on destroyed buildings after an airstrike was carried out over the city of Jisr al-Shughur in Idlib province in Syria, on 6 May 2018. Photo: Hadi Harrat/Anadolu Agency/Getty Images.

Summary

  • Military operations are taking place with increasing frequency in densely populated areas. Such operations result in loss of life and harm to civilians, as well as damage to civilian objects, (including infrastructure providing essential services). In order to protect civilians, it is imperative that armed forces and groups comply with the rules of international humanitarian law on the conduct of hostilities, including the rule of proportionality.
  • The rule of proportionality prohibits attacks which may be expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated. This research paper analyses the key steps that belligerents must take to give effect to the rule, with a particular focus on one side of proportionality assessments – the expected incidental harm.
  • Those undertaking proportionality assessments before or during an attack must consider whether the expected harm will be caused by the attack, and whether that harm could be expected (that is, was it reasonably foreseeable).
  • For the purpose of proportionality assessments, injury to civilians includes disease, and there is no reason in principle to exclude mental harm, even though it is currently challenging to identify and quantify it. Damage to civilian objects includes damage to elements of the natural environment.
  • Once the incidental harm to be considered has been identified, a value or weight must be assigned to it. This is then balanced against the value or weight of the military advantage anticipated from the attack to determine whether the harm would be excessive.
  • In the determination of whether the expected incidental harm would be excessive compared to the anticipated military advantage, ‘excessive’ is a wide but not indeterminate standard.
  • Belligerents should develop methodologies so that those planning and deciding attacks are provided with all necessary information on expected incidental harm, and to assist them in assigning weight to the incidental harm to be considered.
  • If it becomes apparent that the rule of proportionality will be contravened, the attack in question must be cancelled or suspended.
  • Clarification of the law is important in ensuring compliance with the rule of proportionality, but a culture of compliance within armed forces and groups, inculcated by their leaders, is also crucial.




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Secrets and Spies: UK Intelligence Accountability After Iraq and Snowden

Secrets and Spies: UK Intelligence Accountability After Iraq and Snowden Book sysadmin 15 January 2020

How can democratic governments hold intelligence and security agencies to account when what they do is largely secret? Jamie Gaskarth explores how intelligence professionals view accountability in the context of 21st century politics.

Using the UK as a case study, this book provides the first systematic exploration of how accountability is understood inside the secret world. It is based on new interviews with current and former UK intelligence practitioners, as well as extensive research into the performance and scrutiny of the UK intelligence machinery.

The result is the first detailed analysis of how intelligence professionals view their role, what they feel keeps them honest, and how far external overseers impact on their work.

The UK gathers material that helps inform global decisions on such issues as nuclear proliferation, terrorism, transnational crime, and breaches of international humanitarian law. On the flip side, the UK was a major contributor to the intelligence failures leading to the Iraq war in 2003, and its agencies were complicit in the widely discredited U.S. practices of torture and ‘rendition’ of terrorism suspects. UK agencies have come under greater scrutiny since those actions, but it is clear that problems remain.

Secrets and Spies is the result of a British Academy funded project (SG151249) on intelligence accountability. The book is published as part of the Insights series.

Praise for Secrets and Spies

Open society is increasingly defended by secret means. For this reason, oversight has never been more important. This book offers a new exploration of the widening world of accountability for UK intelligence, encompassing informal as well as informal mechanisms. It substantiates its claims well, drawing on an impressive range of interviews with senior figures. This excellent book offers both new information and fresh interpretations. It will have a major impact.

Richard Aldrich, Professor of International Security, University of Warwick, UK

About the author

Jamie Gaskarth is Professor of Foreign Policy and International Relations at The Open University. He was previously senior lecturer at the University of Birmingham where he taught strategy and decision-making. His research focused on the ethical dilemmas of leadership and accountability in intelligence, foreign policy, and defence. He is author/editor or co-editor of six books and served on the Academic Advisory panel for the 2015 UK National Security Strategy and Strategic Defence and Security Review.

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War Time: Temporality and the Decline of Western Military Power

War Time: Temporality and the Decline of Western Military Power Book dora.popova 22 February 2021

In War Time the Western way of war, its pace and timing, are discussed and analysed by experts who question the West’s ability to maintain its military superiority given the political and strategic failures of interventions in Iraq and Afghanistan.

In War Time, war studies experts examine the trajectory of Western military power. They discuss conflicting perceptions of time anchored within Western political and military institutions, and the Western attachment to fast-paced warfare at the expense of longer-term political solutions.

Divided into three sections, the book covers ‘civic militarism’ and the trajectory of Western power, Western perceptions of time and the international normative order, and military operations and temporality. War Time explains why the West has been overwhelmingly powerful on the battlefield and yet strategically and politically weak as exemplified by the return of the Taliban and the hasty evacuation of troops and personnel from Afghanistan.

The book identifies policies that decision-makers must adopt to stave off the decline of Western military dominance.

This book is part of the Insights series.

 

Watch the event

A special event was held in March 2021 to mark the launch of the book. View the event here.

Praise for War Time

War Time is a provocative consideration of the many aspects of modern military power in politics and international affairs. Though the nature of war doesn’t change, this book is particularly relevant given the changing character of modern war as we see in the Caucasus, Ukraine, the Sahel, and the Indo-Pacific region. Essential reading for political leaders, diplomats, and strategic thinkers.

Lt. Gen. (Ret.) Ben Hodges, Pershing Chair in Strategic Studies, Center for European Policy Analysis; Commander, United States Army Europe, 2014–2017

About the editors

Sten Rynning is professor of war studies at the University of Southern Denmark.

Olivier Schmitt is professor with special responsibilities at the Center for War Studies, University of Southern Denmark, and currently director of research and studies at the French Institute for Higher National Defence Studies.

Amelie Theussen is assistant professor at the Center for War Studies, University of 
Southern Denmark.

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Mycobacteria excise DNA damage in 12- or 13-nucleotide-long oligomers by prokaryotic-type dual incisions and performs transcription-coupled repair [Genomics and Proteomics]

In nucleotide excision repair, bulky DNA lesions such as UV-induced cyclobutane pyrimidine dimers are removed from the genome by concerted dual incisions bracketing the lesion, followed by gap filling and ligation. So far, two dual-incision patterns have been discovered: the prokaryotic type, which removes the damage in 11–13-nucleotide-long oligomers, and the eukaryotic type, which removes the damage in 24–32-nucleotide-long oligomers. However, a recent study reported that the UvrC protein of Mycobacterium tuberculosis removes damage in a manner analogous to yeast and humans in a 25-mer oligonucleotide arising from incisions at 15 nt from the 3´ end and 9 nt from the 5´ end flanking the damage. To test this model, we used the in vivo excision assay and the excision repair sequencing genome-wide repair mapping method developed in our laboratory to determine the repair pattern and genome-wide repair map of Mycobacterium smegmatis. We find that M. smegmatis, which possesses homologs of the Escherichia coli uvrA, uvrB, and uvrC genes, removes cyclobutane pyrimidine dimers from the genome in a manner identical to the prokaryotic pattern by incising 7 nt 5´ and 3 or 4 nt 3´ to the photoproduct, and performs transcription-coupled repair in a manner similar to E. coli.




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Optimized incorporation of an unnatural fluorescent amino acid affords measurement of conformational dynamics governing high-fidelity DNA replication [DNA and Chromosomes]

DNA polymerase from bacteriophage T7 undergoes large, substrate-induced conformational changes that are thought to account for high replication fidelity, but prior studies were adversely affected by mutations required to construct a Cys-lite variant needed for site-specific fluorescence labeling. Here we have optimized the direct incorporation of a fluorescent un-natural amino acid, (7-hydroxy-4-coumarin-yl)-ethylglycine, using orthogonal amber suppression machinery in Escherichia coli. MS methods verify that the unnatural amino acid is only incorporated at one position with minimal background. We show that the single fluorophore provides a signal to detect nucleotide-induced conformational changes through equilibrium and stopped-flow kinetic measurements of correct nucleotide binding and incorporation. Pre-steady-state chemical quench methods show that the kinetics and fidelity of DNA replication catalyzed by the labeled enzyme are largely unaffected by the unnatural amino acid. These advances enable rigorous analysis to establish the kinetic and mechanistic basis for high-fidelity DNA replication.




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Boy who survived life support withdrawal confirms “medicine is a science of uncertainty,” says judge




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Lack of evidence for interventions offered in UK fertility centres




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Preserving fertility in girls and young women with cancer




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Public Service, Accountability and Delivery in Malawi

Public Service, Accountability and Delivery in Malawi 17 October 2018 — 12:00PM TO 1:00PM Anonymous (not verified) 11 October 2018 Chatham House, London

On 21 May 2019, Malawi will hold presidential, parliamentary and local ward elections. Public concerns of periodic food shortages and power outages, together with continuing fiscal uncertainty amidst spiralling public debt, bring added significance to this electoral process and beyond as well as significant pressures on the next government. Vice President Saulos Chilima‘s decision to form a new party, the United Transformation Party (UTM), as well as the return of former president Joyce Banda to mainstream politics, mean that with such issues at stake, and political discourse dominated by allegations of corruption, Malawi’s leaders across the spectrum will need clear policy focus to address the country’s significant challenges and meet citizens’ needs.
Vice President Chilima will discuss the formation of the UTM and how to foster intra-party democracy. He will present its approach to poverty reduction, addressing economic instability and challenges ahead of next year’s elections.
THIS EVENT IS NOW FULL AND REGISTRATION HAS CLOSED.




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Water, Energy and Development in Angola: From Ambition to Actuality

Water, Energy and Development in Angola: From Ambition to Actuality 13 December 2018 — 5:00PM TO 6:00PM Anonymous (not verified) 28 November 2018 Chatham House, London

Many Angolans continue to face severe difficulties in accessing the country’s water and energy supplies, with over two-thirds of the population currently unable to connect to the national grid and two-fifths lacking access to drinking water. This already unequal picture is further amplified by the overwhelming concentration of power consumption in the capital: Luanda currently accounts for 70-75 per cent of consumption but supply remains patchy and marred by power cuts. At the core of the government response is an increased engagement with the private sector – including in the construction and modernization of dams and several projects to improve water infrastructure – and progress has been evident in installed power generation capacity which increased by 500MW between 2002 and 2012. Ultimately, a more equitable distribution of energy and water can provide significant benefits for Angola’s economy and citizens.
At this event, HE João Baptista Borges will discuss progress made and challenges faced by Angola’s government in pursuit of water and energy provision and the priorities and prospects for the delivery of targeted improvements in future.
Attendance at this event is by invitation only.




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South Africa’s 2019 Election: Polling Data and Party Prospects

South Africa’s 2019 Election: Polling Data and Party Prospects 13 March 2019 — 12:30PM TO 1:30PM Anonymous (not verified) 7 March 2019 Chatham House, London

On 8 May 2019, South Africans will vote in their sixth national election. Incumbent President Cyril Ramaphosa is leading his ANC party campaign, which promises inclusive economic growth and social transformation, including through a sustainable land reform programme. However, public frustrations with the party’s record of service delivery and government corruption after 25 years in power could threaten the ANC’s electoral dominance especially in urban areas.

At this meeting, Professor David Everatt, head of the Wits School of Governance and political pollster, will present polling data and discuss the prospects and strategies of the main parties and their leaders ahead of the May election.

Attendance at this event is by invitation only.




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COVID-19 in South Africa: Leadership, Resilience and Inequality

COVID-19 in South Africa: Leadership, Resilience and Inequality Expert comment sysadmin 7 May 2020

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.

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 leadership

Ramaphosa 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 thinking

As 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 R500 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.




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Webinar: Finding Solutions to Insecurity in Cabo Delgado

Webinar: Finding Solutions to Insecurity in Cabo Delgado 16 June 2020 — 3:00PM TO 4:30PM Anonymous (not verified) 9 June 2020

Since October 2017, armed attacks in Cabo Delgado, Northern Mozambique have increased in intensity and the spread has widened. Over 1,000 people are thought to have died, and an unknown number of homes and public buildings destroyed. Reports suggest that more than 100,000 people have been internally displaced by these attacks that have been attributed to an armed Islamist sect.
Yet very little is known about who the attackers are, what their strategic objectives are and on whose domestic and international support they rely. Developing multi-faceted solutions to this insecurity will require detailed understanding of the drivers of this extremism, its connection to local informal and illicit economic activity, and the social and structural roots of disenfranchisement and disenchantment.
At this online event, the speakers explore the structural causes, drivers and dynamics of the armed attacks in Cabo Delgado, including the regional and international aspects of the situation.




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South Africa’s foreign policy: Reflections on the United Nations Security Council and the African Union

South Africa’s foreign policy: Reflections on the United Nations Security Council and the African Union 20 January 2021 — 2:00PM TO 3:00PM Anonymous (not verified) 8 January 2021 Online

HE Dr Naledi Pandor, South Africa’s Minister of International Relations and Cooperation, discusses South Africa’s role in pursuing its regional and global goals.

To receive joining instructions, please finalise your registration by clicking the link below. Once you have registered you will receive a confirmation email from Zoom, which will include the unique joining link you will need to attend.

In 2019-2020, South Africa served its third term as a non-permanent member of the UN Security Council, seeking to strengthen its role as a bridge-builder and further justify a more permanent role for the country and continent on the body.

In February 2021, South Africa will also conclude its time as Chair of the African Union, having used its tenure to promote peace and security issues, including closer cooperation with the UNSC, and advance regional economic integration.

South Africa took up these roles at a time of global and regional upheaval. As COVID-19 tested countries’ commitment to cooperation over isolation, South Africa coordinated regional responses to address the challenges of stressed public health systems, vaccine strategies, and economic stimulus and debt support across Africa.

Its leadership has been further tested by ongoing and emerging insecurity in the Sahel, and in Cabo Delgado in neighbouring Mozambique. The crux of its regional strategy remains squaring the circle between promoting regional economic cooperation while protecting its own domestic economic priorities.

At this event, HE Dr Naledi Pandor, Minister of International Relations and Cooperation of the Republic of South Africa, reflects on the country’s two years on the UNSC and one year of chairing the AU, and discuss South Africa’s role in pursuing regional and global goals.

This event will also be broadcast live on the Chatham House Africa Programme’s Facebook page.

Read event transcript. 




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South Africa’s ANC party policy conference 2022: Outcomes and prospects

South Africa’s ANC party policy conference 2022: Outcomes and prospects 10 August 2022 — 1:00PM TO 2:00PM Anonymous (not verified) 4 August 2022 Online

Paul Mashatile, Treasurer-General of the African National Congress (ANC), discusses the outcomes of the 6th ANC Policy Conference 2022.

The African National Congress (ANC) recently concluded its 6th National Policy Conference in Johannesburg, in the year that the ANC has declared ‘The Year of Unity and Renewal to Defend and Advance South Africa’s Democratic Gains’. The conference was a precursor to the party’s 55th National Elective Conference to be held in December.

The conference has come less than a year after municipal polls in which the ANC garnered less than 50 per cent of votes, its lowest since 1994. Many believe internal factionalism is impeding party reform and hampering its ability to address unemployment and entrenched inequality.

At this webinar, Paul Mashatile, Treasurer-General of the ANC, will discuss the outcomes of the ANC Policy Conference 2022, including measures to accelerate inclusive growth, job creation and a just energy transition.

This event will also be broadcast live on the Chatham House Africa Programme’s Facebook page.




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Association between prediabetes and risk of cardiovascular disease and all cause mortality: systematic review and meta-analysis




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NICE recommends hybrid closed loop systems for poorly controlled type 1 diabetes




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Challenges in diabetes and obesity: five minutes with . . . Jonathan Valabhji




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Artificial pancreases for type 1 diabetes: Better access is “watershed moment”—but delivery is key




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Scarlett McNally: Preventing obesity is different from curing it—and even more urgent




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US food manufacturer can say that eating yogurt reduces risk of type 2 diabetes, says FDA




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Type 1 diabetes: Randox removes adverts after claims that it was using fear to sell genetic test




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Covid-19: Progression to clinical type 1 diabetes accelerated after infection, study suggests




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People with type 1 diabetes and disordered eating need joined-up care, says coroner after woman’s death