Carnosine (β-alanyl-l-histidine) and anserine (β-alanyl-3-methyl-l-histidine) are abundant peptides in the nervous system and skeletal muscle of many vertebrates. Many in vitro and in vivo studies demonstrated that exogenously added carnosine can improve muscle contraction, has antioxidant activity, and can quench various reactive aldehydes. Some of these functions likely contribute to the proposed anti-aging activity of carnosine. However, the physiological role of carnosine and related histidine-containing dipeptides (HCDs) is not clear. In this study, we generated a mouse line deficient in carnosine synthase (Carns1). HCDs were undetectable in the primary olfactory system and skeletal muscle of Carns1-deficient mice. Skeletal muscle contraction in these mice, however, was unaltered, and there was no evidence for reduced pH-buffering capacity in the skeletal muscle. Olfactory tests did not reveal any deterioration in 8-month-old mice lacking carnosine. In contrast, aging (18–24-month-old) Carns1-deficient mice exhibited olfactory sensitivity impairments that correlated with an age-dependent reduction in the number of olfactory receptor neurons. Whereas we found no evidence for elevated levels of lipoxidation and glycation end products in the primary olfactory system, protein carbonylation was increased in the olfactory bulb of aged Carns1-deficient mice. Taken together, these results suggest that carnosine in the olfactory system is not essential for information processing in the olfactory signaling pathway but does have a role in the long-term protection of olfactory receptor neurons, possibly through its antioxidant activity.

Distinct cell types emerge from embryonic stem cells through a precise and coordinated execution of gene expression programs during lineage commitment. This is established by the action of lineage specific transcription factors along with chromatin complexes. Numerous studies have focused on epigenetic factors that affect embryonic stem cells (ESC) self-renewal and pluripotency. However, the contribution of chromatin to lineage decisions at the exit from pluripotency has not been as extensively studied. Using a pooled epigenetic shRNA screen strategy, we identified chromatin-related factors critical for differentiation toward mesodermal and endodermal lineages. Here we reveal a critical role for the chromatin protein, ARID4B. Arid4b-deficient mESCs are similar to WT mESCs in the expression of pluripotency factors and their self-renewal. However, ARID4B loss results in defects in up-regulation of the meso/endodermal gene expression program. It was previously shown that Arid4b resides in a complex with SIN3A and HDACS 1 and 2. We identified a physical and functional interaction of ARID4B with HDAC1 rather than HDAC2, suggesting functionally distinct Sin3a subcomplexes might regulate cell fate decisions Finally, we observed that ARID4B deficiency leads to increased H3K27me3 and a reduced H3K27Ac level in key developmental gene loci, whereas a subset of genomic regions gain H3K27Ac marks. Our results demonstrate that epigenetic control through ARID4B plays a key role in the execution of lineage-specific gene expression programs at pluripotency exit.

Stromal interaction molecule 1 (STIM1) plays a pivotal role in store-operated Ca2+ entry (SOCE), an essential mechanism in cellular calcium signaling and in maintaining cellular calcium balance. Because O-GlcNAcylation plays pivotal roles in various cellular function, we examined the effect of fluctuation in STIM1 O-GlcNAcylation on SOCE activity. We found that both increase and decrease in STIM1 O-GlcNAcylation impaired SOCE activity. To determine the molecular basis, we established STIM1-knockout HEK293 (STIM1-KO-HEK) cells using the CRISPR/Cas9 system and transfected STIM1 WT (STIM1-KO-WT-HEK), S621A (STIM1-KO-S621A-HEK), or T626A (STIM1-KO-T626A-HEK) cells. Using these cells, we examined the possible O-GlcNAcylation sites of STIM1 to determine whether the sites were O-GlcNAcylated. Co-immunoprecipitation analysis revealed that Ser621 and Thr626 were O-GlcNAcylated and that Thr626 was O-GlcNAcylated in the steady state but Ser621 was not. The SOCE activity in STIM1-KO-S621A-HEK and STIM1-KO-T626A-HEK cells was lower than that in STIM1-KO-WT-HEK cells because of reduced phosphorylation at Ser621. Treatment with the O-GlcNAcase inhibitor Thiamet G or O-GlcNAc transferase (OGT) transfection, which increases O-GlcNAcylation, reduced SOCE activity, whereas treatment with the OGT inhibitor ST045849 or siOGT transfection, which decreases O-GlcNAcylation, also reduced SOCE activity. Decrease in SOCE activity due to increase and decrease in O-GlcNAcylation was attributable to reduced phosphorylation at Ser621. These data suggest that both decrease in O-GlcNAcylation at Thr626 and increase in O-GlcNAcylation at Ser621 in STIM1 lead to impairment of SOCE activity through decrease in Ser621 phosphorylation. Targeting STIM1 O-GlcNAcylation could provide a promising treatment option for the related diseases, such as neurodegenerative diseases.

α-Linked galactose is a common carbohydrate motif in nature that is processed by a variety of glycoside hydrolases from different families. Terminal Galα1–3Gal motifs are found as a defining feature of different blood group and tissue antigens, as well as the building block of the marine algal galactan λ-carrageenan. The blood group B antigen and linear α-Gal epitope can be processed by glycoside hydrolases in family GH110, whereas the presence of genes encoding GH110 enzymes in polysaccharide utilization loci from marine bacteria suggests a role in processing λ-carrageenan. However, the structure–function relationships underpinning the α-1,3-galactosidase activity within family GH110 remain unknown. Here we focus on a GH110 enzyme (PdGH110B) from the carrageenolytic marine bacterium Pseudoalteromonas distincta U2A. We showed that the enzyme was active on Galα1–3Gal but not the blood group B antigen. X-ray crystal structures in complex with galactose and unhydrolyzed Galα1–3Gal revealed the parallel β-helix fold of the enzyme and the structural basis of its inverting catalytic mechanism. Moreover, an examination of the active site reveals likely adaptations that allow accommodation of fucose in blood group B active GH110 enzymes or, in the case of PdGH110, accommodation of the sulfate groups found on λ-carrageenan. Overall, this work provides insight into the first member of a predominantly marine clade of GH110 enzymes while also illuminating the structural basis of α-1,3-galactoside processing by the family as a whole.

α1-antitrypsin (AAT) regulates the activity of multiple proteases in the lungs and liver. A mutant of AAT (E342K) called ATZ forms polymers that are present at only low levels in the serum and induce intracellular protein inclusions, causing lung emphysema and liver cirrhosis. An understanding of factors that can reduce the intracellular accumulation of ATZ is of great interest. We now show that calreticulin (CRT), an endoplasmic reticulum (ER) glycoprotein chaperone, promotes the secretory trafficking of ATZ, enhancing the media:cell ratio. This effect is more pronounced for ATZ than with AAT and is only partially dependent on the glycan-binding site of CRT, which is generally relevant to substrate recruitment and folding by CRT. The CRT-related chaperone calnexin does not enhance ATZ secretory trafficking, despite the higher cellular abundance of calnexin-ATZ complexes. CRT deficiency alters the distributions of ATZ-ER chaperone complexes, increasing ATZ-BiP binding and inclusion body formation and reducing ATZ interactions with components required for ER-Golgi trafficking, coincident with reduced levels of the protein transport protein Sec31A in CRT-deficient cells. These findings indicate a novel role for CRT in promoting the secretory trafficking of a protein that forms polymers and large intracellular inclusions. Inefficient secretory trafficking of ATZ in the absence of CRT is coincident with enhanced accumulation of ER-derived ATZ inclusion bodies. Further understanding of the factors that control the secretory trafficking of ATZ and their regulation by CRT could lead to new therapies for lung and liver diseases linked to AAT deficiency.

The actin cytoskeleton is of profound importance to cell shape, division, and intracellular force generation. Profilins bind to globular (G-)actin and regulate actin filament formation. Although profilins are well-established actin regulators, the distinct roles of the dominant profilin, profilin 1 (PFN1), versus the less abundant profilin 2 (PFN2) remain enigmatic. In this study, we use interaction proteomics to discover that PFN2 is an interaction partner of the actin N-terminal acetyltransferase NAA80, and further confirm this by analytical ultracentrifugation. Enzyme assays with NAA80 and different profilins demonstrate that PFN2 binding specifically increases the intrinsic catalytic activity of NAA80. NAA80 binds PFN2 through a proline-rich loop, deletion of which abrogates PFN2 binding. Small-angle X-ray scattering shows that NAA80, actin, and PFN2 form a ternary complex and that NAA80 has partly disordered regions in the N-terminus and the proline-rich loop, the latter of which is partly ordered upon PFN2 binding. Furthermore, binding of PFN2 to NAA80 via the proline-rich loop promotes binding between the globular domains of actin and NAA80, and thus acetylation of actin. However, the majority of cellular NAA80 is stably bound to PFN2 and not to actin, and we propose that this complex acetylates G-actin before it is incorporated into filaments. In conclusion, we reveal a functionally specific role of PFN2 as a stable interactor and regulator of the actin N-terminal acetyltransferase NAA80, and establish the modus operandi for NAA80-mediated actin N-terminal acetylation, a modification with a major impact on cytoskeletal dynamics.

Cation diffusion facilitator (CDF) proteins are a conserved family of divalent transition metal cation transporters. CDF proteins are usually composed of two domains: the transmembrane domain, in which the metal cations are transported through, and a regulatory cytoplasmic C-terminal domain (CTD). Each CDF protein transports either one specific metal or multiple metals from the cytoplasm, and it is not known whether the CTD takes an active regulatory role in metal recognition and discrimination during cation transport. Here, the model CDF protein MamM, an iron transporter from magnetotactic bacteria, was used to probe the role of the CTD in metal recognition and selectivity. Using a combination of biophysical and structural approaches, the binding of different metals to MamM CTD was characterized. Results reveal that different metals bind distinctively to MamM CTD in terms of their binding sites, thermodynamics, and binding-dependent conformations, both in crystal form and in solution, which suggests a varying level of functional discrimination between CDF domains. Furthermore, these results provide the first direct evidence that CDF CTDs play a role in metal selectivity. We demonstrate that MamM's CTD can discriminate against Mn2+, supporting its postulated role in preventing magnetite formation poisoning in magnetotactic bacteria via Mn2+ incorporation.

Connexin (Cx) protein forms hemichannels and gap junctional channels, which play diverse and profound roles in human physiology and diseases. Gap junctions are arrays of intercellular channels formed by the docking of two hemichannels from adjacent cells. Each hexameric hemichannel contains the same or different Cx isoform. Although homomeric Cxs forms have been largely described functionally and structurally, the stoichiometry and arrangement of heteromeric Cx channels remain unknown. The latter, however, are widely expressed in human tissues and variation might have important implications on channel function. Investigating properties of heteromeric Cx channels is challenging considering the high number of potential subunit arrangements and stoichiometries, even when only combining two Cx isoforms. To tackle this problem, we engineered an HA tag onto Cx26 or Cx30 subunits and imaged hemichannels that were liganded by Fab-epitope antibody fragments via atomic force microscopy. For Cx26-HA/Cx30 or Cx30-HA/Cx26 heteromeric channels, the Fab-HA binding distribution was binomial with a maximum of three Fab-HA bound. Furthermore, imaged Cx26/Cx30-HA triple liganded by Fab-HA showed multiple arrangements that can be derived from the law of total probabilities. Atomic force microscopy imaging of ringlike structures of Cx26/Cx30-HA hemichannels confirmed these findings and also detected a polydisperse distribution of stoichiometries. Our results indicate a dominant subunit stoichiometry of 3Cx26:3Cx30 with the most abundant subunit arrangement of Cx26-Cx26-Cx30-Cx26-Cx30-Cx30. To our knowledge, this is the first time that the molecular architecture of heteromeric Cx channels has been revealed, thus providing the basis to explore the functional effect of these channels in biology.

The bacterial enhancer-binding protein (bEBP) FlrC, controls motility and colonization of Vibrio cholerae by regulating the transcription of class-III flagellar genes in σ54-dependent manner. However, the mechanism by which FlrC regulates transcription is not fully elucidated. Although, most bEBPs require nucleotides to stimulate the oligomerization necessary for function, our previous study showed that the central domain of FlrC (FlrCC) forms heptamer in a nucleotide-independent manner. Furthermore, heptameric FlrCC binds ATP in “cis-mediated” style without any contribution from sensor I motif 285REDXXYR291 of the trans protomer. This atypical ATP binding raises the question of whether heptamerization of FlrC is solely required for transcription regulation, or if it is also critical for ATPase activity. ATPase assays and size exclusion chromatography of the trans-variants FlrCC-Y290A and FlrCC-R291A showed destabilization of heptameric assembly with concomitant abrogation of ATPase activity. Crystal structures showed that in the cis-variant FlrCC-R349A drastic shift of Walker A encroached ATP-binding site, whereas the site remained occupied by ADP in FlrCC-Y290A. We postulated that FlrCC heptamerizes through concentration-dependent cooperativity for maximal ATPase activity and upon heptamerization, packing of trans-acting Tyr290 against cis-acting Arg349 compels Arg349 to maintain proper conformation of Walker A. Finally, a Trp quenching study revealed binding of cyclic-di-GMP with FlrCC. Excess cyclic-di-GMP repressed ATPase activity of FlrCC through destabilization of heptameric assembly, especially at low concentration of protein. Systematic phylogenetic analysis allowed us to propose similar regulatory mechanisms for FlrCs of several Vibrio species and a set of monotrichous Gram-negative bacteria.

Investigations of bacterial resistance strategies can aid in the development of new antimicrobial drugs as a countermeasure to the increasing worldwide prevalence of bacterial antibiotic resistance. One such strategy involves the TipA class of transcription factors, which constitute minimal autoregulated multidrug resistance (MDR) systems against diverse antibiotics. However, we have insufficient information regarding how antibiotic binding induces transcriptional activation to design molecules that could interfere with this process. To learn more, we determined the crystal structure of SkgA from Caulobacter crescentus as a representative TipA protein. We identified an unexpected spatial orientation and location of the antibiotic-binding TipAS effector domain in the apo state. We observed that the α6–α7 region of the TipAS domain, which is canonically responsible for forming the lid of antibiotic-binding cleft to tightly enclose the bound antibiotic, is involved in the dimeric interface and stabilized via interaction with the DNA-binding domain in the apo state. Further structural and biochemical analyses demonstrated that the unliganded TipAS domain sterically hinders promoter DNA binding but undergoes a remarkable conformational shift upon antibiotic binding to release this autoinhibition via a switch of its α6–α7 region. Hence, the promoters for MDR genes including tipA and RNA polymerases become available for transcription, enabling efficient antibiotic resistance. These insights into the molecular mechanism of activation of TipA proteins advance our understanding of TipA proteins, as well as bacterial MDR systems, and may provide important clues to block bacterial resistance.

Iron is an essential micronutrient, and, in the case of bacteria, its availability is commonly a growth-limiting factor. However, correct functioning of cells requires that the labile pool of chelatable “free” iron be tightly regulated. Correct metalation of proteins requiring iron as a cofactor demands that such a readily accessible source of iron exist, but overaccumulation results in an oxidative burden that, if unchecked, would lead to cell death. The toxicity of iron stems from its potential to catalyze formation of reactive oxygen species that, in addition to causing damage to biological molecules, can also lead to the formation of reactive nitrogen species. To avoid iron-mediated oxidative stress, bacteria utilize iron-dependent global regulators to sense the iron status of the cell and regulate the expression of proteins involved in the acquisition, storage, and efflux of iron accordingly. Here, we survey the current understanding of the structure and mechanism of the important members of each of these classes of protein. Diversity in the details of iron homeostasis mechanisms reflect the differing nutritional stresses resulting from the wide variety of ecological niches that bacteria inhabit. However, in this review, we seek to highlight the similarities of iron homeostasis between different bacteria, while acknowledging important variations. In this way, we hope to illustrate how bacteria have evolved common approaches to overcome the dual problems of the insolubility and potential toxicity of iron.

Chorismate mutase (CM), an essential enzyme at the branch-point of the shikimate pathway, is required for the biosynthesis of phenylalanine and tyrosine in bacteria, archaea, plants, and fungi. MtCM, the CM from Mycobacterium tuberculosis, has less than 1% of the catalytic efficiency of a typical natural CM and requires complex formation with 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase for high activity. To explore the full potential of MtCM for catalyzing its native reaction, we applied diverse iterative cycles of mutagenesis and selection, thereby raising kcat/Km 270-fold to 5 × 105 m−1s−1, which is even higher than for the complex. Moreover, the evolutionarily optimized autonomous MtCM, which had 11 of its 90 amino acids exchanged, was stabilized compared with its progenitor, as indicated by a 9 °C increase in melting temperature. The 1.5 Å crystal structure of the top-evolved MtCM variant reveals the molecular underpinnings of this activity boost. Some acquired residues (e.g. Pro52 and Asp55) are conserved in naturally efficient CMs, but most of them lie beyond the active site. Our evolutionary trajectories reached a plateau at the level of the best natural enzymes, suggesting that we have exhausted the potential of MtCM. Taken together, these findings show that the scaffold of MtCM, which naturally evolved for mediocrity to enable inter-enzyme allosteric regulation of the shikimate pathway, is inherently capable of high activity.

Identification of antibody-binding epitopes is crucial to understand immunological mechanisms. It is of particular interest for allergenic proteins with high cross-reactivity as observed in the lipid transfer protein (LTP) syndrome, which is characterized by severe allergic reactions. Art v 3, a pollen LTP from mugwort, is frequently involved in this cross-reactivity, but no antibody-binding epitopes have been determined so far. To reveal human IgE-binding regions of Art v 3, we produced three murine high-affinity mAbs, which showed 70–90% coverage of the allergenic epitopes from mugwort pollen–allergic patients. As reliable methods to determine structural epitopes with tightly interacting intact antibodies under native conditions are lacking, we developed a straightforward NMR approach termed hydrogen/deuterium exchange memory (HDXMEM). It relies on the slow exchange between the invisible antigen-mAb complex and the free 15N-labeled antigen whose 1H-15N correlations are detected. Due to a memory effect, changes of NH protection during antibody binding are measured. Differences in H/D exchange rates and analyses of mAb reactivity to homologous LTPs revealed three structural epitopes: two partially cross-reactive regions around α-helices 2 and 4 as well as a novel Art v 3–specific epitope at the C terminus. Protein variants with exchanged epitope residues confirmed the antibody-binding sites and revealed strongly reduced IgE reactivity. Using the novel HDXMEM for NMR epitope mapping allowed identification of the first structural epitopes of an allergenic pollen LTP. This knowledge enables improved cross-reactivity prediction for patients suffering from LTP allergy and facilitates design of therapeutics.

The dimeric ectonucleotidase CD73 catalyzes the hydrolysis of AMP at the cell surface to form adenosine, a potent suppressor of the immune response. Blocking CD73 activity in the tumor microenvironment can have a beneficial effect on tumor eradication and is a promising approach for cancer therapy. Biparatopic antibodies binding different regions of CD73 may be a means to antagonize its enzymatic activity. A panel of biparatopic antibodies representing the pairwise combination of 11 parental monoclonal antibodies against CD73 was generated by Fab-arm exchange. Nine variants vastly exceeded the potency of their parental antibodies with ≥90% inhibition of activity and subnanomolar EC50 values. Pairing the Fabs of parents with nonoverlapping epitopes was both sufficient and necessary whereas monovalent antibodies were poor inhibitors. Some parental antibodies yielded potent biparatopics with multiple partners, one of which (TB19) producing the most potent. The structure of the TB19 Fab with CD73 reveals that it blocks alignment of the N- and C-terminal CD73 domains necessary for catalysis. A separate structure of CD73 with a Fab (TB38) which complements TB19 in a particularly potent biparatopic shows its binding to a nonoverlapping site on the CD73 N-terminal domain. Structural modeling demonstrates a TB19/TB38 biparatopic antibody would be unable to bind the CD73 dimer in a bivalent manner, implicating crosslinking of separate CD73 dimers in its mechanism of action. This ability of a biparatopic antibody to both crosslink CD73 dimers and fix them in an inactive conformation thus represents a highly effective mechanism for the inhibition of CD73 activity.

Sirtuin 6, SIRT6, is critical for both glucose and lipid homeostasis and is involved in maintaining genomic stability under conditions of oxidative DNA damage such as those observed in age-related diseases. There is an intense search for modulators of SIRT6 activity, however, not many specific activators have been reported. Long acyl-chain fatty acids have been shown to increase the weak in vitro deacetylase activity of SIRT6 but this effect is modest at best. Herein we report that electrophilic nitro-fatty acids (nitro-oleic acid and nitro-conjugated linoleic acid) potently activate SIRT6. Binding of the nitro-fatty acid to the hydrophobic crevice of the SIRT6 active site exerted a moderate activation (2-fold at 20 μm), similar to that previously reported for non-nitrated fatty acids. However, covalent Michael adduct formation with Cys-18, a residue present at the N terminus of SIRT6 but absent from other isoforms, induced a conformational change that resulted in a much stronger activation (40-fold at 20 μm). Molecular modeling of the resulting Michael adduct suggested stabilization of the co-substrate and acyl-binding loops as a possible additional mechanism of SIRT6 activation by the nitro-fatty acid. Importantly, treatment of cells with nitro-oleic acid promoted H3K9 deacetylation, whereas oleic acid had no effect. Altogether, our results show that nitrated fatty acids can be considered a valuable tool for specific SIRT6 activation, and that SIRT6 should be considered as a molecular target for in vivo actions of these anti-inflammatory nitro-lipids.

Members of the B-cell lymphoma (BCL-2) protein family regulate mitochondrial outer membrane permeabilization (MOMP), a phenomenon in which mitochondria become porous and release death-propagating complexes during the early stages of apoptosis. Pro-apoptotic BCL-2 proteins oligomerize at the mitochondrial outer membrane during MOMP, inducing pore formation. Of current interest are endogenous factors that can inhibit pro-apoptotic BCL-2 mitochondrial outer membrane translocation and oligomerization. A mitochondrial-derived peptide, Humanin (HN), was reported being expressed from an alternate ORF in the mitochondrial genome and inhibiting apoptosis through interactions with the pro-apoptotic BCL-2 proteins. Specifically, it is known to complex with BAX and BID. We recently reported the fibrillation of HN and BAX into β-sheets. Here, we detail the fibrillation between HN and BID. These fibers were characterized using several spectroscopic techniques, protease fragmentation with mass analysis, and EM. Enhanced fibrillation rates were detected with rising temperatures or pH values and the presence of a detergent. BID fibers are similar to those produced using BAX; however, the structures differ in final conformations of the BCL-2 proteins. BID fibers display both types of secondary structure in the fiber, whereas BAX was converted entirely to β-sheets. The data show that two distinct segments of BID are incorporated into the fiber structure, whereas other portions of BID remain solvent-exposed and retain helical structure. Similar analyses show that anti-apoptotic BCL-xL does not form fibers with humanin. These results support a general mechanism of sequestration of pro-apoptotic BCL-2 proteins into fibers by HN to inhibit MOMP.

Abnormal changes of neuronal Tau protein, such as phosphorylation and aggregation, are considered hallmarks of cognitive deficits in Alzheimer's disease. Abnormal phosphorylation is thought to precede aggregation and therefore to promote aggregation, but the nature and extent of phosphorylation remain ill-defined. Tau contains ∼85 potential phosphorylation sites, which can be phosphorylated by various kinases because the unfolded structure of Tau makes them accessible. However, methodological limitations (e.g. in MS of phosphopeptides, or antibodies against phosphoepitopes) led to conflicting results regarding the extent of Tau phosphorylation in cells. Here we present results from a new approach based on native MS of intact Tau expressed in eukaryotic cells (Sf9). The extent of phosphorylation is heterogeneous, up to ∼20 phosphates per molecule distributed over 51 sites. The medium phosphorylated fraction Pm showed overall occupancies of ∼8 Pi (± 5) with a bell-shaped distribution; the highly phosphorylated fraction Ph had 14 Pi (± 6). The distribution of sites was highly asymmetric (with 71% of all P-sites in the C-terminal half of Tau). All sites were on Ser or Thr residues, but none were on Tyr. Other known posttranslational modifications were near or below our detection limit (e.g. acetylation, ubiquitination). These findings suggest that normal cellular Tau shows a remarkably high extent of phosphorylation, whereas other modifications are nearly absent. This implies that abnormal phosphorylations at certain sites may not affect the extent of phosphorylation significantly and do not represent hyperphosphorylation. By implication, the pathological aggregation of Tau is not likely a consequence of high phosphorylation.

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Viral infection is one environmental factor that may contribute to the initiation of pancreatic β-cell destruction during the development of autoimmune diabetes. Picornaviruses, such as encephalomyocarditis virus (EMCV), induce a pro-inflammatory response in islets leading to local production of cytokines, such as IL-1, by resident islet leukocytes. Furthermore, IL-1 is known to stimulate β-cell expression of iNOS and production of the free radical nitric oxide. The purpose of this study was to determine whether nitric oxide contributes to the β-cell response to viral infection. We show that nitric oxide protects β-cells against virally mediated lysis by limiting EMCV replication. This protection requires low micromolar, or iNOS-derived, levels of nitric oxide. At these concentrations nitric oxide inhibits the Krebs enzyme aconitase and complex IV of the electron transport chain. Like nitric oxide, pharmacological inhibition of mitochondrial oxidative metabolism attenuates EMCV-mediated β-cell lysis by inhibiting viral replication. These findings provide novel evidence that cytokine signaling in β-cells functions to limit viral replication and subsequent β-cell lysis by attenuating mitochondrial oxidative metabolism in a nitric oxide–dependent manner.

Cellular energy demands are met by uptake and metabolism of nutrients like glucose. The principal transcriptional regulator for adapting glycolytic flux and downstream pathways like de novo lipogenesis to glucose availability in many cell types is carbohydrate response element–binding protein (ChREBP). ChREBP is activated by glucose metabolites and post-translational modifications, inducing nuclear accumulation and regulation of target genes. Here we report that ChREBP is modified by proline hydroxylation at several residues. Proline hydroxylation targets both ectopically expressed ChREBP in cells and endogenous ChREBP in mouse liver. Functionally, we found that specific hydroxylated prolines were dispensable for protein stability but required for the adequate activation of ChREBP upon exposure to high glucose. Accordingly, ChREBP target gene expression was rescued by re-expressing WT but not ChREBP that lacks hydroxylated prolines in ChREBP-deleted hepatocytes. Thus, proline hydroxylation of ChREBP is a novel post-translational modification that may allow for therapeutic interference in metabolic diseases.

The synthesis of cholesterol requires more than 20 enzymes, many of which are intricately regulated. Post-translational control of these enzymes provides a rapid means for modifying flux through the pathway. So far, several enzymes have been shown to be rapidly degraded through the ubiquitin–proteasome pathway in response to cholesterol and other sterol intermediates. Additionally, several enzymes have their activity altered through phosphorylation mechanisms. Most work has focused on the two rate-limiting enzymes: 3-hydroxy-3-methylglutaryl CoA reductase and squalene monooxygenase. Here, we review current literature in the area to define some common themes in the regulation of the entire cholesterol synthesis pathway. We highlight the rich variety of inputs controlling each enzyme, discuss the interplay that exists between regulatory mechanisms, and summarize findings that reveal an intricately coordinated network of regulation along the cholesterol synthesis pathway. We provide a roadmap for future research into the post-translational control of cholesterol synthesis, and no doubt the road ahead will reveal further twists and turns for this fascinating pathway crucial for human health and disease.

Methionine, through S-adenosylmethionine, activates a multifaceted growth program in which ribosome biogenesis, carbon metabolism, and amino acid and nucleotide biosynthesis are induced. This growth program requires the activity of the Gcn4 transcription factor (called ATF4 in mammals), which facilitates the supply of metabolic precursors that are essential for anabolism. However, how Gcn4 itself is regulated in the presence of methionine is unknown. Here, we discover that Gcn4 protein levels are increased by methionine, despite conditions of high cell growth and translation (in which the roles of Gcn4 are not well-studied). We demonstrate that this mechanism of Gcn4 induction is independent of transcription, as well as the conventional Gcn2/eIF2α-mediated increased translation of Gcn4. Instead, when methionine is abundant, Gcn4 phosphorylation is decreased, which reduces its ubiquitination and therefore degradation. Gcn4 is dephosphorylated by the protein phosphatase 2A (PP2A); our data show that when methionine is abundant, the conserved methyltransferase Ppm1 methylates and alters the activity of the catalytic subunit of PP2A, shifting the balance of Gcn4 toward a dephosphorylated, stable state. The absence of Ppm1 or the loss of the PP2A methylation destabilizes Gcn4 even when methionine is abundant, leading to collapse of the Gcn4-dependent anabolic program. These findings reveal a novel, methionine-dependent signaling and regulatory axis. Here methionine directs the conserved methyltransferase Ppm1 via its target phosphatase PP2A to selectively stabilize Gcn4. Through this, cells conditionally modify a major phosphatase to stabilize a metabolic master regulator and drive anabolism.

Pyrroline-5-carboxylate reductase 1 (PYCR1) catalyzes the biosynthetic half-reaction of the proline cycle by reducing Δ1-pyrroline-5-carboxylate (P5C) to proline through the oxidation of NAD(P)H. Many cancers alter their proline metabolism by up-regulating the proline cycle and proline biosynthesis, and knockdowns of PYCR1 lead to decreased cell proliferation. Thus, evidence is growing for PYCR1 as a potential cancer therapy target. Inhibitors of cancer targets are useful as chemical probes for studying cancer mechanisms and starting compounds for drug discovery; however, there is a notable lack of validated inhibitors for PYCR1. To fill this gap, we performed a small-scale focused screen of proline analogs using X-ray crystallography. Five inhibitors of human PYCR1 were discovered: l-tetrahydro-2-furoic acid, cyclopentanecarboxylate, l-thiazolidine-4-carboxylate, l-thiazolidine-2-carboxylate, and N-formyl l-proline (NFLP). The most potent inhibitor was NFLP, which had a competitive (with P5C) inhibition constant of 100 μm. The structure of PYCR1 complexed with NFLP shows that inhibitor binding is accompanied by conformational changes in the active site, including the translation of an α-helix by 1 Å. These changes are unique to NFLP and enable additional hydrogen bonds with the enzyme. NFLP was also shown to phenocopy the PYCR1 knockdown in MCF10A H-RASV12 breast cancer cells by inhibiting de novo proline biosynthesis and impairing spheroidal growth. In summary, we generated the first validated chemical probe of PYCR1 and demonstrated proof-of-concept for screening proline analogs to discover inhibitors of the proline cycle.

Oxygen regulates hypoxia-inducible factor (HIF) transcription factors to control cell metabolism, erythrogenesis, and angiogenesis. Whereas much has been elucidated about how oxygen regulates HIF, whether lipids affect HIF activity is un-known. Here, using cultured cells and two animal models, we demonstrate that lipoprotein-derived fatty acids are an independent regulator of HIF. Decreasing extracellular lipid supply inhibited HIF prolyl hydroxylation, leading to accumulation of the HIFα subunit of these heterodimeric transcription factors comparable with hypoxia with activation of downstream target genes. The addition of fatty acids to culture medium suppressed this signal, which required an intact mitochondrial respiratory chain. Mechanistically, fatty acids and oxygen are distinct signals integrated to control HIF activity. Finally, we observed lipid signaling to HIF and changes in target gene expression in developing zebrafish and adult mice, and this pathway operates in cancer cells from a range of tissues. This study identifies fatty acids as a physiological modulator of HIF, defining a mechanism for lipoprotein regulation that functions in parallel to oxygen.

Peptidoglycan (PG) is an essential constituent of the bacterial cell wall. During cell division, the machinery responsible for PG synthesis localizes mid-cell, at the septum, under the control of a multiprotein complex called the divisome. In Escherichia coli, septal PG synthesis and cell constriction rely on the accumulation of FtsN at the division site. Interestingly, a short sequence of FtsN (Leu75–Gln93, known as EFtsN) was shown to be essential and sufficient for its functioning in vivo, but what exactly this sequence is doing remained unknown. Here, we show that EFtsN binds specifically to the major PG synthase PBP1b and is sufficient to stimulate its biosynthetic glycosyltransferase (GTase) activity. We also report the crystal structure of PBP1b in complex with EFtsN, which demonstrates that EFtsN binds at the junction between the GTase and UB2H domains of PBP1b. Interestingly, mutations to two residues (R141A/R397A) within the EFtsN-binding pocket reduced the activation of PBP1b by FtsN but not by the lipoprotein LpoB. This mutant was unable to rescue the ΔponB-ponAts strain, which lacks PBP1b and has a thermosensitive PBP1a, at nonpermissive temperature and induced a mild cell-chaining phenotype and cell lysis. Altogether, the results show that EFtsN interacts with PBP1b and that this interaction plays a role in the activation of its GTase activity by FtsN, which may contribute to the overall septal PG synthesis and regulation during cell division.

Towards just transition in Africa: Green financing for urban energy solutions and job creation 9 June 2022 — 7:30AM TO 11:00AM Anonymous (not verified) 18 May 2022 Nairobi and online

This event explores the major openings and potential impediments to the development of a just transition policy in Africa.

Global climate policies towards a ‘just transition’ under the Paris Agreement should also align with and support African states’ national sustainable development priorities. In particular, the need for decent and fair job creation and the establishment of sufficient, resilient and sustainable power supply, accessible to all, and efficient energy use.

Achieving green growth requires innovative and more accessible financing models, especially as wealthy nations’ financial pledges have fallen short. Ahead of the ‘African COP27’ set to take place in Egypt in November 2022, there is a need for transformational strategic thinking and context-specific action from African governments, civil society, businesses and financiers in their green financing demands and national implementation plans.

Sustainable urban energy solutions represent a critical zone of opportunity for the development of new and more reliable green finance pathways. Africa’s rapidly expanding cities present a significant economic opportunity and source of growth. However, urban centres are also where income and energy inequalities are at their starkest. The acceleration of sustainable energy generation and use could have a transformative impact on SMEs and livelihoods across value chains.

At this event, participants will discuss the major openings and potential impediments to the development of a credible ‘just transition’ policy in Africa towards net zero goals, with a particular focus on establishing and enhancing links between green financing innovation, employment creation, sustainable power supply and generation, and sustainable energy usage and consumption in an urban environment.

This event is held in partnership with the Pan African Climate Justice Alliance (PACJA). It is part of a series on Towards Just Transition: Connecting Green Financing and Sustainable Job Creation in Africa, supported by the Chatham House Sustainability Accelerator.

This event will be held in English and French with simultaneous interpretation.

Towards just transition in Africa: Green financing for nature-based solutions and rural resilience 21 July 2022 — 9:30AM TO 1:00PM Anonymous (not verified) 30 June 2022 Libreville and online

This hybrid event in Libreville explores just transition policy and green financing for nature-based solutions, with a particular focus on the integration of job creation priorities in conservation and rural resilience.

Global climate policies towards a ‘just transition’ under the Paris Agreement should align with and support African states’ national sustainable development priorities – in particular, the need for decent and fair job creation, as well as resilient and sustainable land, environment, and ecosystem management policies.

Achieving green growth requires innovative and more accessible financing models, especially as wealthy nations’ financial pledges have fallen short. Ahead of the ‘African COP27’ set to take place in Egypt in November 2022, there is a need for transformational strategic thinking and context-specific action from African governments, civil society, businesses and financiers, in their green financing demands and national implementation plans.

Preservation of biodiversity and nature is not only critical in the global fight against climate change but is also vital for conservation-based economic development. Natural capital stocks, such as terrestrial and marine ecosystems and biodiversity, produce benefits that support societal and individual well-being and economic prosperity, such as clean air, fresh water, regulation of water flows and pollination of crops – while also acting as important carbon sinks. Financing environmental protection must go beyond compensation and contribute to creating fair social and economic conditions for incentivizing conservation.

At this hybrid event in Libreville, participants will discuss green financing for nature-based solutions, particularly the integration of plans for job creation in conservation and rural resilience within just transition planning.

This event is part of a series on Towards Just Transition: Connecting Green Financing and Sustainable Job Creation in Africa, supported by the Chatham House Sustainability Accelerator.

This event will be held in French and English with simultaneous interpretation.

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

COP27: Navigating a difficult road to Sharm El-Sheikh Expert comment NCapeling 6 July 2022

Against a backdrop of rising urgency, COP27 in Egypt will bring all aspects of climate action into the spotlight – but especially the role of the host country.

As COP26 drew to a close in Glasgow, Egyptian officials announced their priorities for COP27, emphasizing climate finance and climate adaptation – a new approach given previous COPs mainly focused on mitigation, reducing emissions to limit climate damage.

This was followed by the COP27 presidency outlining its vision at MENA Climate Week 2022 to achieve ‘substantive and equal progress’ on all aspects of the negotiations, and Egypt emphasizing its intention to focus on implementing existing carbon reduction targets rather than pushing for further carbon cuts.

Egypt argues it is hosting COP27 on behalf of African nations and that, while it is promoting the interests of the developing world, it will be an impartial arbiter. However it is also useful to consider its priorities from the Egyptian government’s perspective.

Agenda drivers

Egypt has long prioritized climate finance and adaptation because it remains in need of technical and financial support to adapt, especially in agriculture and tourism.

It plans to expand its access to climate funding and investment, an area in which Egypt has been relatively successful as it currently receives 27 per cent of all multilateral climate finance in the MENA region and has issued the region’s first sovereign green bonds.

With public debt currently 94 per cent of GDP, Egyptian officials have also called for debt relief for Egypt and other developing countries.

Egypt’s Climate Change Strategy reflects this approach, aiming to enhance Egypt’s rank on the Climate Change Performance Index in order to ‘attract more investments and acquire more climate funding’.

Limiting the mitigation scope and the focus on finance also echoes Egypt’s own reluctance to make carbon reduction commitments. The Egyptian nationally determined contribution (NDC) – its 2030 pledge under the Paris Agreement – does not include any quantifiable emission reduction targets.

Egypt is one of only a few countries which failed to submit an updated NDC in 2021 and its upcoming update will not include an economy-wide carbon reduction target.

Egypt has also never published a long-term strategy and has no decarbonization plans despite independent estimates it should cut rising emissions by one-quarter by 2030, and by two-thirds by 2050 to be aligned with the Paris Agreement. This partly explains why observers rate Egypt’s climate action as highly insufficient.

Furthermore, Egypt’s championing of ‘moving from pledges to implementation’ without having quantifiable carbon reduction pledges of its own effectively exempts it from both pledging and implementation.

As a developing country, Egypt’s negotiating position is supported by UNFCCC provisions which recognize differentiated responsibilities and respective capabilities of nations.

Its proposal to focus COP27 on the implementation of climate action and finance pledges is important in consolidating progress. But not pushing for more emission reductions at this critical moment risks derailing global decarbonization momentum and undermining global climate action.

According to optimistic estimates, if current climate pledges were implemented the world would still remain on track for 2°C of warming by the end of the century, with far worse impacts than if warming was curbed at 1.5°C.

Under a 2°C scenario, 37 per cent of the global population could regularly be exposed to extreme heat waves compared to 14 per cent in a 1.5°C warmer world, with developing countries expected to be worst-affected.

A 2°C trajectory also runs the risk of tipping points such as the melting of ice sheets in Antarctica and Greenland, triggering runaway climate change. Time to change the warming trajectory is running out as the latest IPCC assessment warns the window of opportunity is now ‘brief and rapidly closing’, and the UN Secretary General recently called for faster carbon cuts by the end of 2022 to avoid a ‘climate catastrophe’.

A different energy transition

Egypt opted not to join any of the voluntary sectoral coalitions at COP26 on reducing methane, clean energy transition, transition to zero-emissions vehicles, or moving beyond oil and gas.

This position is explained by its growing role as an exporter and advocate for fossil gas in the energy transition. Egypt is the second-largest producer of natural gas in Africa and is emerging as a fossil gas hub for the eastern Mediterranean, which is shaping its domestic energy policy.

Its 59GW electricity generation capacity is almost double the peak demand and is dominated by gas-powered electricity generation, which currently represents 42 per cent of all Africa’s gas generation.

Egypt’s climate policy is also shaped by fossil gas, and its national Climate Change Strategy encourages the expansion of gas use by promoting a transition to compressed natural gas for vehicles, the expansion of its domestic natural gas network – despite having universal access to electricity – and shifting to a gas-fuelled shipping sector.

Egypt also voiced support for other African countries to extract and deploy fossil gas and oil resources, making it one of the protagonists of the ‘great fossil gas pushback’. These advocates defend the right of developing countries to deploy fossil gas as a ‘transition fuel’ and champion its necessity to solve energy poverty.

But their position is not shared by all African and developing countries, and is rejected by some civil society groups, who argue it risks locking in greenhouse gases and local emissions for decades as well as delaying future development of low carbon energy systems.

Egypt’s huge spare generation capacity has contributed to a slowdown in renewable energy projects over the past two years. With renewables representing just 6GW, Egypt is expected to miss its renewable energy target for 2022, set at 20 per cent of generating capacity.

Engaging Egypt better

But these positions are more malleable than they seem, and Egypt is open to dialogue – not just on refining the COP27 agenda but also on reviewing its own climate priorities and leveraging its energy sector for a more ambitious transition.

Now is the moment to launch an African vaccine industry The World Today mhiggins.drupal 31 July 2022

The continent plans to make 60 per cent of its vaccines by 2040. After the failure of the world to help in the pandemic, it’s high time, says Ngozi Erondu.

The lack of an African vaccine industry has been a glaring concern for decades. Before the pandemic, 99 per cent of Africa’s vaccines were manufactured outside the continent. As well as endangering the lives of millions, this situation has inhibited social and economic progress on the continent.

In response, the Africa Centres for Disease Control and Prevention (Africa CDC) has undertaken an ambitious plan, outlined in the Partnerships for African Vaccine Manufacturing (PAVM) Framework for Action, to develop the nascent African vaccine manufacturing sector into an end-to-end industry by 2040. The framework aims to raise the share of African-manufactured vaccines used across the continent to 60 per cent by 2040, or the equivalent to up to 1.7 billion doses annually.

Seven of every 10 vaccines used in Africa are currently donated through Gavi, the Vaccine Alliance. Most are administered within childhood immunization programmes and are largely manufactured either in India, or by  multinational vaccine manufacturers in North America or Japan.

Vaccine donations have inhibited the development in Africa of vaccines and other countermeasures against diseases.

Though the Ebola virus was discovered in Central Africa in 1976, vaccine development was not adequately funded until it emerged in Europe in 2014. Human monkeypox resurfaced in Nigeria in 2017, yet the global Coalition for Epidemic Preparedness Innovations only targeted it for vaccine development in July this year.

The pandemic highlighted Africa’s fatal dependency on imported vaccines. Only 20 per cent of Africans are fully vaccinated against Covid-19, due to the failure of countries in the Global North to ensure the equitable distribution of vaccines via the COVAX facility to 40 per cent of the world’s most vulnerable people. 

The pandemic also confirmed that Africa could not rely on fellow states of the Global South. At the height of the Delta variant outbreak in early 2021, India halted vaccine exports to Africa, where only 1.5 per cent of the population had at that time received any vaccine doses.

After decades of discussions, there are signs that Africa could soon succeed in creating its own vaccine industry. First, the 55-member African Union is in the process of establishing the African Medicines Agency, a regional regulatory body. 
 

‘The new public health order’

Additionally, the African Export-Import Bank and African Development Bank (AfDB) have established a foundation to provide financial and strategic support for the development of the pharmaceutical industry and the consolidation of regional vaccination programmes in Africa (the foundation would potentially negotiate intellectual property rights and licensing issues but that remains to be seen).

Second, studies show there is an emerging middle class in Africa. In a 2011 report by the AfDB, this was estimated at some 56 million households. Potentially, this means many people will be able to buy vaccines and medicines made in Africa.

About a third of African countries currently pay for their vaccine needs. According to PAVM forecasts, the value of the total African market could reach between $3 billion and $17 billion by 2040.

The recent entry into effect of the African Continental Free Trade Area should also prove conducive to African vaccine development. Through economic integration, free movement and harmonized regional standards, countries that invest in their biopharmaceutical and medical technology sectors may attract employees, regional and international businesses, and investment. Further, the pandemic has encouraged people to relocate to countries with, or planning for, universal healthcare.

Building an African pharmaceutical industry from the ground up could take much longer than two decades and cost tens of billions of dollars. Nevertheless, the moment seems ripe, and timely support has been forthcoming from influential regional actors, including Rwandan President Paul Kagame, South Africa’s Cyril Ramaphosa, and private sector business executives, including the Zimbabwean-born billionaire Strive Masiyiwa.

With a pandemic treaty embedding equity in prevention, preparedness and response some way off, and given the limitations surrounding the recent World Trade Organization compromise on the TRIPS waiver – which temporarily waives Covid-19 vaccine patent protections for poorer countries – it is doubly important for Africa to build up its own pharmaceutical industry and emergency systems. 

In 2021, John Nkengasong, then director of Africa CDC, wrote of the necessity of a post-pandemic ‘new public health order’ for Africa. Such a change may threaten the global health organizations, industries and institutes who derive payment from ‘saving Africa’ during emergencies. Additionally, through strengthening Africa CDC, other actors such as the World Health Organization may find that they have a diminished strategic role on the continent.
 
While Africa should not dismiss these valuable and long-standing partnerships, it must take the opportunity to advance its interests and to assume leadership in this important area.

A booming tech sector can unleash pan-African trade The World Today mhiggins.drupal 31 July 2022

The new African Continental Free Trade Area must embrace hyperscale data centres, cross-border digital payments and other innovations to realise its potential.

The Africa Continental Free Trade Area (AfCFTA) not only lays the groundwork for a single market across the continent, it can act as a driving force to unleash the full potential of the technology revolution that is under way across the African continent. 

To help achieve this, the AfCFTA must go beyond simply lowering barriers to the movement of goods and services, to what the World Bank calls an ‘FDI [foreign direct investment] deep scenario’. This requires harmonizing policies on investment, competition, intellectual property rights and e-commerce to encourage FDI at a greater scale. 

The World Bank estimates that the AfCFTA could increase income across the continent by 7 per cent by 2035 (an additional $445 billion), mainly by boosting intra-regional trade in manufactured goods and lifting approximately 40 million people from extreme poverty. Under an FDI deep scenario, the projected income growth jumps to 9 per cent by 2035, supporting 50 million people out of extreme poverty. 

The initial focus of the AfCFTA is on movement of goods and services and the associated financial flows through the establishment of the Pan-African Payment and Settlement System (PAPSS), a technology that enables instant local currency payment across Africa without first converting to a hard currency. In addition, harmonizing policies and easing the movement of data could enable technology to accelerate the anticipated AfCFTA income growth.

Global venture capital is pouring in

There is no doubt the African tech industry is growing. In 2021, 681 African technology companies raised $5.2 billion in equity venture funding, up from $2 billion in 2019, according to Partech Partners’ annual Africa Tech Venture Capital report. 

It is understandable why the industry has attracted global venture capital. While tech businesses are often initially focused on meeting needs in their home markets, most have a strong desire to tap into the pan-African market, with its 1.3 billion consumers across 54 countries and a combined GDP of $3.4 trillion. This in turn should attract global venture capital to invest in Africa. 

The AfCFTA has created a framework for technology-led companies to scale across the continent in a way that will impact digital infrastructure, logistics, energy and much else. For example, Africa’s hyperscale data centre capacity would benefit from the ability to locate centres in the lowest cost jurisdiction with the best energy availability and to use that to power cloud storage across the continent.

Yet various regulatory constraints, including the desire for each state to own its population’s data on local servers, prevent that. As a result, African data centres are less competitive than those in America and China. 

Similarly, logistics and other sectors would be transformed if the information on goods in transit, such as digital customs documentation, could move easily across borders while being tracked across all 54 countries. Financial services would also benefit from the ability to pay across borders in a low-cost, frictionless way.

Fintech companies should be encouraged to build technology solutions linking to PAPSS and other initiatives to accelerate the adoption-of-use cases that PAPSS supports – such as intra-Africa instant payment, embedded finance and remittances services.

AfCFTA may also unlock mergers and acquisitions (M&A) activity among African and international firms. Technology companies are using M&A to enter new markets, as the international payments platform Stripe did when it acquired the Nigerian business Paystack, and the payments business MFS Africa did when it took over the fintech start-up Baxi. 

Governments and regulators must support innovation

Given the difficulty of a country-by-country organic growth strategy across Africa, M&A is likely to increase in various technology sectors over the next few years. With the anticipated ease of doing business that the AfCFTA could facilitate, we are likely to witness further welcome consolidation, creating larger corporates that create more jobs and increase tax revenues. 

To unlock the benefits that technology will bring, governments and regulators need to play a supportive role in encouraging innovation. They will need to ensure the appropriate consumer protections are in place without stifling creativity through regulation, inefficiencies or rent-seeking. 

At the same time, governments and regulators should not permit themselves to be held to ransom by dominant incumbents, such as banks and mobile operators in the fintech space, at the expense of stifling technology companies looking to disrupt their respective industries. 

Only then will the AfCFTA allow Africa to benefit from its tech potential. 

Risana Zitha writes this article in a personal capacity

Why Africa needs to be in space The World Today mhiggins.drupal 1 August 2022

From agriculture and navigation to banking and tele-education, satellite technology can have a huge impact on rapidly developing societies, says Val Munsami.

Africa’s socio-economic and environmental development is widely acknowledged as being crucial to its growth and long-term sustainability – and the prosperity of its more than one billion residents. 

Increasingly, though, attention is also turning to the contribution that the space industry can make to progress on the continent. Space-based products and services have a critical role to play in meeting national and continental priorities, as underpinned by the UN’s Sustainable Development Goals and the African Union’s Agenda 2063 – the bloc’s strategic framework for development, democracy and peace. 

With this in the mind of policymakers, the African Union’s space policy and strategy is embedded in Agenda 2063 as one of its 15 key programmes. It guides the sector’s development and the nascent African Space Agency, to become operational later this year from its headquarters in Egypt.

The continental agency is expected to leverage the benefits of space science and technology for socio-economic and environmental development. It will lead on bridging the space divide, especially for those countries that do not have a focus on, or activities in, space science and technology – and simultaneously inject some momentum into improving capabilities of existing national space programmes.

The African Union’s commitment to space has accelerated the growth of the African space industry. More than 20 national space agencies or space-related institutions have been established on the continent over the past five or so years. 

Our modern lifestyles are intimately dependent on space products and services. Meteorological and communication satellites are placed in geostationary orbits at an altitude of 36,000km above the equator. At this point above the Earth, they complete one orbit every 24 hours in the direction of the planet’s rotation, appearing, essentially, motionless – and providing a constant gaze on the same geographic location.

They provide a wealth of information that fuels the everyday services we take for granted, but that are essential for our everyday lives, from health to education to the economy.

From their vantage point, geostationary orbit satellites provide our daily weather reports, monitor climate-related cycles and offer a platform for near-instantaneous communications across the globe to relay multimedia, live sporting events and up-to-the-minute global news. 

This lightning-fast communication is also indispensable for tele-education and tele-medicine, by which professionals in urban areas can deliver educational content and health services to rural schools and clinics, respectively. Banking transactions also rely on telecommunication satellites to communicate between an automated teller machine and the data servers located at the bank. 

How satellites can detect disease

Other satellites are placed in low Earth orbits. These complete on average one polar orbit around the Earth every 100 minutes. Because the planet rotates across the plane of the orbit, such a satellite eventually covers the whole Earth, which is immensely useful for remote sensing and navigation and positioning applications. 

Remote sensing applications provide a myriad of products and services, including monitoring the state of our natural resources, observing ship traffic in our coastal economic zones and providing information for precision farming that can help a farmer decide, for example, when to irrigate and how much fertilizer to use.

They can also detect changes that might indicate encroaching water-borne diseases, aid peacekeeping missions and help ensure public safety and security. Navigation applications are vital for aviation and marine navigation, whereas positioning applications are important for safety-of-life services. 

Another way that positioning applications in developing countries are put to good use is the assignment of geolocation addresses to dwellings in informal settlements where postbox addresses do not exist. This then allows the overlaying of key vector data about populations on to geophysical base maps. This type of data is vital for town planning in terms of how many schools and clinics are needed to serve the population, and the extent of the road, water, sanitation and electrical infrastructure needed.

The rich source of information derived from satellites, overlaid with in-situ data, is vital for evidence-based decision and policymaking. Datasets accessed from historical archives can be used to observe the time evolution of environmental and statistical data. 

When policy decisions are taken, we can utilize the same satellite and in-situ platforms to monitor progress after their implementation. The utility of data to inform decision-making is being enhanced through the adoption of AI and big-data analytics, which is placing key information at our disposal in near real time. 

It is therefore not surprising to notice the increasing focus on space science and technology activities on the continent. However, to ensure the effective uptake and utilization of space products and services, certain building blocks are needed to establish robust national and regional space ecosystems. 

Africa’s route into space

These ecosystems must include four primary elements to function: the human capital required to establish and operate the space initiatives; a significant industry base to capitalize on the commercial aspects of the space sector; the requisite infrastructure needed to support the space value chain; and international cooperation to ensure knowledge transfer and diffusion – so that we don’t have to reinvent the wheel.

The applications and problem-solving innovations provided by space products and services are endless. To take advantage of this, Africa needs strong governance and institutional architectures. 

The evolution of the space ecosystem on the continent must be premised on key instruments such as a space policy – which areas to focus on and why – and a space strategy that outlines which programmes and performance indicators to pursue. 

The conceptualization of a space ecosystem is by no means a simple endeavour and there is certainly a dearth of skills and experience on the African continent to establish effective and relevant space ecosystems. 

There are many institutions leading efforts to build space capacity and skills on the continent, such as the International Space University in France, which offers programmes that provide a holistic overview of the complex global space sector, and the African Space Leadership Institute, which has been recently created to develop capacity in space policy, law and strategy. 

With the right approach, commitment and investment, Africa can rapidly change the fate of its citizens by effectively using space science and technology to support and drive its developmental agenda.

Culture notes: Europe's broken promises to Africa The World Today mhiggins.drupal 1 August 2022

Europe’s ‘gas grab’ in Africa is just the latest abuse of its relationship with the continent, says Catherine Fieschi.

When Emmanuel Macron made one of his first visits to Africa as France’s recently elected young president in 2017, his speech at Ouagadougou University in Burkina Faso was designed to set the tone for a new relationship between his country and African countries. 

‘There no longer is a French policy for Africa,’ he said.

This was a signal away from ‘la Françafrique’, with its post-colonial accents and the propping up of regimes friendly to France, to something that was more strategic, equitable and transparent – more partnership and less tutelage. 

And Europe seemed to be following suit. In March 2020 the European Union and Africa decided that they would redefine their relationship. The European Commission unveiled its vision for a ‘comprehensive strategy with Africa’. The roadmap would give Africa significantly more say over the nature and extent of the relationship, more choice and more political agency.

But what, today, is left of these aspirations? Despite repeated statements, Europe seems to be saying one thing and doing another. 

Earlier this year, after the long-awaited 6th annual EU-African Union summit in Brussels, South African president Cyril Ramaphosa was frank when he summed up the gap between stated ambitions and the current relationship. The pandemic-weary Global South had reason to be wary. Ramaphosa laid out missed opportunities, disappointment and the low expectations that act as self-fulfilling prophecies. 

Europe’s changing focus in Africa 

From the apparent high point of the Ouagadougou speech, Macron has now turned to the Organization Internationale de la Francophonie (OIF) in Africa for geopolitical purposes. His primary aim is to combat the rise of Islamist militants and terrorism in the Sahel as well as to tackle the growing influence of China and Russia in the region. 

Russian inroads – via the security firm Wagner in Mali, for instance – have given France further cause to use the OIF to counter destabilization activities. Both the United Kingdom and France train African military in the Sahel, but now, with the end of France’s anti-insurgent Operation Barkhane in Mali, the subsequent withdrawal of French troops and the increasingly established presence of the Wagner group, the security situation in the region is expected to deteriorate dramatically and become increasingly impermeable to European interests and forces.

As for development aid, Britain’s Integrated Review of Security, Defence, Development and Foreign Policy makes no bones about the fact that Asia is now a priority over Africa.

The relationship between Africa and Britain is being transformed as a result, most obviously through the cuts in development aid, with African aid cut by 66 per cent in 2021. But the nature of the relationship, which has become both more conditional and more transactional, has also changed. 

The UK is emphasizing human rights and ‘free societies’, but also pushing for free market principles rather than the kind of state involvement that some African countries often prefer as a road to accelerated and more autonomous development. 

The future of energy exports and COP27

The issue of energy exports points to what will most likely trigger the greatest disappointment in the next few years – climate and climate finance. 

Green energy deals, like the $8.5 billion COP26 package from the EU, United States and UK to South Africa, look far more problematic now in the light of Europe’s African gas-grab. Indeed, Europe is importing as much African gas as it can after the invasion of Ukraine by Russia reduced supplies. Yet African countries are still being told to curb their own use of ‘dirty’ energy. 

As an illustration, Nigeria holds 3 per cent of the world’s gas reserves, but has barely tapped them, while 40 per cent of its output is exported to Europe. In April, Italy closed deals to buy gas from Angola and the Republic of Congo, while Germany did the same with Senegal.
 

At COP15 in Copenhagen in 2009, developed countries pledged an annual $100 billion in climate finance to developing countries for both adaptation and mitigation. But pledges have never really materialized. The aid agency Oxfam estimates that only about a third of the money has been delivered. Climate finance was again the main focus of COP26 – and dismissed by Greta Thunberg as more ‘blah, blah, blah’.

This series of repeated resets, pledges and disappointments tells a story – indeed, several stories. First and foremost, it is one of arrogance and betrayal. That much is obvious. But it is also a story about stories – about how the narratives elaborated by various European countries and leaders never amount to more than a sum of transactions. 

Climate change places Europe, and other rich nations, at a crossroads in its relationship with Africa: the former holds the wealth, but also some of the keys and threats to the transition. COP27, to be held in Egypt in November, will be the next chapter in the story. 

Eight ways to build better African cities The World Today mhiggins.drupal 2 August 2022

Young professionals from across the continent tell Emmanuel Adegboye how city life could be improved: from high-speed rail to people-centred urban planning.

Ahmed Elsawy, 33, Director of Talent
Cairo, Egypt
We must amend employment law in Egypt to support individual contractors to match with the global demand for short-term and project-based assignments within the tech and service industries. While we have a new, decent education system, I think we should care more about foreign languages to have a higher rank when it comes to the global competition of skilled workers.

Iman Abubaker, 31, Urban Mobility Project Manager, WRI Africa
Addis Ababa, Ethiopia
Rapid urbanization and increased motorization have exacerbated the city’s urban challenges. Addis Ababa would benefit from safer street design and people-centred city planning. Urban amenities should be located within walking and cycling distances. For longer trips, the city needs to invest in improving the accessibility, safety, integration and multimodality of its public transport system. I would love to see more pockets of green spaces and parks all around the city. 

Bree, 31, Project Manager
Nairobi, Kenya
I have a love-hate relationship with Nairobi. I spent four years smack in the middle of the city while attending the University of Nairobi. Being in the middle of all the hustle and bustle made the transition to a sleepy-ish coastal town easy. I would happily trade matatus [shared taxis] for tuktuks any day. I do miss the conveniences that come with a big city like a 24-hour grocery store and delivery services on those lazy days.

Mfon Bassey, 30, Co-Founder, TalentX Africa
Lagos, Nigeria
The government should improve the road networks and public transport systems, because the common challenge most Lagosians face is commuting from point A to B without traffic. There are so many private cars on the road because the public transport system isn’t optimally efficient yet. Once you take away the commute time most workers spend just to get work done, we’ll surely have happier Lagosians.

Olga Kiconco, 32, Innovation Strategist
Kampala, Uganda
As one of Africa’s fastest-growing cities with a projected 112 per cent population growth by 2035, there are a number of critical changes that need to be made in preparation for this. Our leaders should embrace coherent policies that will catalyze socio-economic transformation. We need to hold them accountable for better infrastructure and delivery of public services, while taking personal responsibility to protect our environment against the prevalent threat of climate change.

Etienne Amougou, 30, Curator/Arts Project Manager
Yaounde, Cameroon
What would make Yaounde better would be a good ecosystem that provides more opportunities for young people. If it was possible, I would like to see the creation of more cultural spaces, like parks, zoos, cinemas and sport areas. Also, we could use a more effective approach to waste management – sometimes we have trash everywhere in the ’hood.

Valentino Fernandez, 23, Writer
Johannesburg, South Africa
 We need better transportation to bridge the inequality gap and allow the youth to access spaces to be inspired and create change. Apartheid spatial planning is still affecting us. People of colour were relegated to the outskirts of the city, and very little has changed. It’s virtually impossible to move out of your childhood home, which means you’re looking at a two-hour commute every morning and two more hours to get home. I would like a reliable, affordable, high-speed rail system.

Jean-Louis Mbaka, 34, Co-Founder and Director, Education at Kinshasa Digital
Kinshasa, DRC
Our youth must receive a sufficient education that is in line with the strategic requirements of their future workplaces. By 2030, more than 130 million jobs in Africa will require digital skills, according to the International Finance Corporation. To close the gap between the conventional educational system and the labour market, our organisation is providing training for digital jobs. Initiatives like ours must be supported if the current and next generations are to have the means for their economic and social advancement. Scaling up investments in vital facilities like the internet is also necessary.

Not the same old African story The World Today mhiggins.drupal 2 August 2022

Nollywood studio boss Mo Abudu and author Dipo Faloyin discuss how Africans are redefining how the world sees them.

Mo Abudu
EbonyLife’s latest TV drama series, Blood Sisters, was in Netflix’s global top 10. It’s a thriller and it may be slightly melodramatic because we Nigerians are melodramatic. But it deals with universal themes. Nigerians are no different to anyone else. I want EbonyLife productions increasingly to appeal to anyone in the world, even if it’s in our language. Oloture, one of our films, was about human trafficking. It was all done in pidgin English and subtitled. I watch a lot of Korean dramas and Spanish dramas that are subtitled. A good story is a good story.

Dipo Faloyin
The influence that African countries have had on the West, from music, food and film to literature, science and technology, is something people find difficult to take seriously. So, it’s good to see Netflix and other production companies take it more seriously. How has your discussion with them changed since the early days?

Mo Abudu
I have been going to an entertainment market in Cannes called Mipcom for about 12 years, and at first no one had any interest in African content. So, we focused on doing local content for local markets. Now, different communities around the world want representation in content that speaks to them. Specific countries are also saying to streamers: ‘What’s your local content strategy?’ 

Netflix was the first of the streamers to come into Africa, and it now has an Africa office. Amazon has also made inroads recently. Disney is arriving. In the United States and Britain, they just need to maintain subscriber numbers, but real growth for them is going to be in Asia and Africa. 

I’m not telling broadcasters or distributors to commission original African content as a charity project – they can make money from this. Within five days of launch, Blood Sisters registered 11 million hours of viewing on Netflix around the world. It was made on a budget five times smaller than productions outside Africa. But we need to be among the gatekeepers, too. 

Moving beyond Hollywood

Dipo Faloyin
The challenge that many creatives across Africa have is that people [elsewhere] don’t necessarily feel like they relate to this continent. They see ‘Africa’ and its cultures as very distant. Instead of intricate, specific stories, simple stories of simple people have been pushed about the continent. 

I still get asked questions like, ‘But, what should we do about Africa’s problems?’ My response is, ‘Stop seeing Africa as just a problem.’ 

Mo Abudu
I was speaking at the Qatar Economic Forum recently and the panel started off talking about the ‘problems of Africa’ – and I had to jump in and say, ‘I get you guys talking about the problems, I’m not an economist, I’m just an entrepreneur, but from an entrepreneurial perspective, we have resources – like cobalt from the Democratic Republic of Congo that’s in all of our mobile phones.’ 

The problem is, we ship out all our resources and by the time they come back to us, they are 10-times more expensive than we can afford. I keep saying that they need to know they need us as much as we need them.
 
Dipo Faloyin
There are certainly issues within the continent like there are everywhere else; but more accurate stories will help people have a better sense of the context in which so many communities and their lives have been built up. 

Mo Abudu
The West doesn’t seem to have any interest in making films about Africa unless it’s about the worst of Africa: the slave trade, the Rwandan genocide, blood diamonds. That seems to be what has defined us. 

Dipo Faloyin
If you ask most people around the world to close their eyes and picture Africa, two images will come up: safari, and poverty and strife. Until the age of 12, I grew up in Lagos, a metropolis with no wild animals running around. There are slums, of course, but also traffic, shopping centres and overpriced restaurants. 

Writers who pitch ideas to Vice.com where I work often still don’t differentiate African countries. They’ll say, ‘There’s been a coup in Mali. Why can’t Africa get its head around democracy?’, and I remind them a small minority of countries on the continent is under any form of authoritarian rule. 

It’s frustrating that this perception hasn’t changed. For us to break through we need big cultural institutions – Hollywood, museums, literature – to allow people from across the regions to tell these stories. We are rarely portrayed as protagonists and forward thinkers. But I’m excited for the future.

Towards democracy in Sudan: Reflections on the transitional period 20 September 2022 — 2:00PM TO 4:00PM Anonymous (not verified) 31 August 2022 Online

In this webinar, panellists discuss the key outcomes of the evaluation workshop and reflect on how the experience of the transition to date should inform the realization of Sudan’s democratic aspirations going forward.

The military coup on 25 October 2021 halted Sudan’s transition to democracy and prospects for sustainable peace. Since then, members of the former regime have regained political influence, with many reinstated to senior positions.

The coup has provoked a strong reaction from the country’s pro-democracy movement and youth-led resistance committees who have led continuous peaceful protests demanding civilian democratic transition, despite a brutal crackdown by state security forces.

Those supportive of the coup have blamed the Forces of Freedom and Change (FFC), a wide coalition of pro-democracy political and civilian groups, for the mistakes of the transitional government.

However, the country’s political, security and economic situation has sharply deteriorated since the military’s action, and the progress achieved by the transitional government has been reversed, leading to an accelerating economic crisis, increased food insecurity and political instability.

The FFC, which played a key role in appointing the transitional government, has acknowledged its errors. In July 2022, it held a workshop in Khartoum, which was broadcast on social media, to evaluate its performance and identify lessons learned, in discussion with civil society actors and activists.

In this webinar, leading pro-democracy movement figures and independent experts discuss the key outcomes of the evaluation workshop and reflect on how the experience of the transition to date should inform the realization of Sudan’s democratic aspirations going forward.

This event is part of a Chatham House Africa programme project on supporting Sudan’s civilian-led democratic transition.

Towards just transition in Africa: Continental coordination on green financing and job creation 6 October 2022 — 7:00AM TO 3:30PM Anonymous (not verified) 8 September 2022 Addis Ababa and online

At this hybrid conference in Addis Ababa, speakers take stock of preparations ahead of the ‘African COP27’ in November and discuss the key priorities for streamlining continental cooperation on policy approaches to just transition.

At this hybrid conference in Addis Ababa, speakers will take stock of policy efforts and preparations ahead of the ‘African COP27’ in November and discuss the key priorities for streamlining continental cooperation on policy approaches to just transition.

Global climate policies towards a ‘just transition’ under the Paris Agreement should align with and support African states’ national sustainable development priorities – in particular, the need for decent and fair job creation, as well as resilient and sustainable land, environment and ecosystem management policies.

They must also be cognizant of African nations’ urgent requirements for sustainable and accessible energy to underpin economic development. Achieving green growth requires innovative and more accessible financing models, especially as wealthy nations’ financial pledges have fallen short. It also requires clarity and cooperation to unlock investment in both renewable and transitional energy.

African countries face collective climate and employment-related challenges. However, policymaking often remains regionally siloed according to differing political, energy sector and ecological realities. There is a need for transformational strategic thinking and context-specific action from African governments, civil society, businesses and financiers, in their green financing demands and national implementation plans.

At this hybrid conference in Addis Ababa, speakers will take stock of policy efforts and preparations ahead of the ‘African COP27’ in November and discuss the key priorities for streamlining continental cooperation on policy approaches to just transition, job creation and green financing.

This event is the third in a series on Towards just transition: Connecting green financing and sustainable job creation in Africa, supported by the Chatham House Sustainability Accelerator.

Sudan’s gold boom: Connections to conflict and transnational impacts 7 December 2022 — 2:00PM TO 3:30PM Anonymous (not verified) 24 November 2022 Online

At this event, experts will discuss Sudan’s gold sector, its connections to conflict, and transnational impacts. 

At this webinar panellists will discuss Sudan’s gold sector, its connections to conflict, and transnational impacts.

Sudan is one of the largest gold producers on the continent, with the industry constituting Sudan’s foremost source of hard currency since the secession of South Sudan in 2011 and resulting loss of oilfields.

The gold rush that has ensued has had important implications for domestic and transnational conflict dynamics. Military actors and armed groups have sought control of gold-producing areas in the peripheries and to capitalize on the flow of labour migrants, against a wider backdrop of conflict partly stemming from contestation for control between central and local actors.

International interests are prominent, including increased Russian involvement in the sector, while gold smuggling has also interlaced with mercenary activity in neighbouring CAR, Chad and Libya.
 
At this event, panellists will discuss Sudan’s gold trade, its connections to conflict, and transnational impacts, including the international politics of Sudan’s gold extraction and role of armed groups. It will also explore the environmental and socio-economic dimensions of gold in Sudan’s border areas. 
 
This roundtable is an output of the Cross-Border Conflict: Evidence, Policy and Trends (XCEPT) research programme, funded by UK Aid from the UK government.
 

Towards just transition in Africa Interview Video NCapeling 23 December 2022

Highlighting key interventions from African policymakers, business leaders, researchers, and civil society voices on green financing and implementation plans.

African countries face collective climate and employment-related challenges. However, policymaking often remains regionally siloed according to differing political, energy sector, and ecological realities.

There is a need for transformational strategic thinking and context-specific action from African governments, civil society, businesses, and financiers, in their green financing demands and national implementation plans.

This video highlights key interventions from policymakers, business leaders, researchers, and civil society voices at a series of events hosted by the Chatham House Africa programme in Nairobi, Libreville, and Addis Ababa in the lead-up to COP27.

The events series, Towards just transition: Connecting green financing and sustainable job creation in Africa, was supported by the Chatham House Sustainability Accelerator and the United Nations Development Programme.

Africa Aware: Towards just transition in Africa Audio NCapeling 1 March 2023

African countries face collective climate and job creation-related challenges, yet policymaking often remains regionally siloed.

This podcast reflects on the key policy messages from the Africa programme’s series on Towards just transition: Connecting green financing and sustainable job creation in Africa.

African countries face collective climate and job creation-related challenges. Yet policymaking often remains regionally siloed according to differing political, energy sector and ecological realities.

This output is part of a stream of work supported by the Chatham House Sustainability Accelerator and the United Nations Development Programme (UNDP). 

Purpose: The ⁶⁸Ga-PSMA PET/CT is a commonly used imaging modality in prostate cancers. However, few studies have compared the diagnostic efficiency between ⁶⁸Ga-PSMA and ¹⁸F-FDG PET/CT and evaluated whether a heterogeneous metabolic phenotype (especially PSMA-FDG+ lesions) exists in patients with castration-resistant prostate cancer (CRPC). We determined the added value of ¹⁸F-FDG PET/CT compared to ⁶⁸Ga-PSMA PET/CT in CRPC patients and identified CRPC patients who may benefit from additional ¹⁸F-FDG PET/CT. Methods: Data of 56 patients with CRPC who underwent both ⁶⁸Ga-PSMA and ¹⁸F-FDG PET/CT from May 2018 to February 2021 were retrospectively analysed. Patients were classified into two groups with or without PSMA-FDG+ lesions. The differences in patient characteristics between the two groups and predictors of patients who having at least one PSMA-FDG+ lesion were analysed. Results: Although both the detection rate (75.0% vs. 51.8%, P = 0.004) and positive lesion number (135 vs. 95) of ⁶⁸Ga-PSMA PET/CT were higher than ¹⁸F-FDG PET/CT, there were still 13/56 (23.2%) patients with at least one PSMA-FDG+ lesion. The prostate-specific antigen (PSA) and Gleason score were both higher in the patients with PSMA-FDG+ lesions than in those without PSMA-FDG+ lesions (P = 0.04 and P<0.001, respectively). Multivariate regression analysis showed that the Gleason score (≥8) and PSA (≥7.9 ng/mL) were associated with the detection rate of patients who had PSMA-FDG+ lesions (P = 0.01 and P = 0.04, respectively). The incidences of having PSMA-FDG+ lesions in low-probability (Gleason score<8 and PSA<7.9 ng/mL), medium-probability (Gleason score≥8 and PSA<7.9 ng/mL or Gleason score<8 and PSA≥7.9 ng/mL), and high-probability (Gleason score≥8 and PSA≥7.9 ng/mL) groups were 0%, 21.7%, and 61.5%, respectively (P<0.001). Conclusion: Gleason score and PSA are significant predictors for PSMA-FDG+ lesions, and CRPC patients with high Gleason score and PSA may benefit from additional ¹⁸F-FDG PET/CT.