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A structural and kinetic survey of GH5_4 endoglucanases reveals determinants of broad substrate specificity and opportunities for biomass hydrolysis [Protein Structure and Folding]

Broad-specificity glycoside hydrolases (GHs) contribute to plant biomass hydrolysis by degrading a diverse range of polysaccharides, making them useful catalysts for renewable energy and biocommodity production. Discovery of new GHs with improved kinetic parameters or more tolerant substrate-binding sites could increase the efficiency of renewable bioenergy production even further. GH5 has over 50 subfamilies exhibiting selectivities for reaction with β-(1,4)–linked oligo- and polysaccharides. Among these, subfamily 4 (GH5_4) contains numerous broad-selectivity endoglucanases that hydrolyze cellulose, xyloglucan, and mixed-linkage glucans. We previously surveyed the whole subfamily and found over 100 new broad-specificity endoglucanases, although the structural origins of broad specificity remained unclear. A mechanistic understanding of GH5_4 substrate specificity would help inform the best protein design strategies and the most appropriate industrial application of broad-specificity endoglucanases. Here we report structures of 10 new GH5_4 enzymes from cellulolytic microbes and characterize their substrate selectivity using normalized reducing sugar assays and MS. We found that GH5_4 enzymes have the highest catalytic efficiency for hydrolysis of xyloglucan, glucomannan, and soluble β-glucans, with opportunistic secondary reactions on cellulose, mannan, and xylan. The positions of key aromatic residues determine the overall reaction rate and breadth of substrate tolerance, and they contribute to differences in oligosaccharide cleavage patterns. Our new composite model identifies several critical structural features that confer broad specificity and may be readily engineered into existing industrial enzymes. We demonstrate that GH5_4 endoglucanases can have broad specificity without sacrificing high activity, making them a valuable addition to the biomass deconstruction toolset.




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High-throughput and site-specific N-glycosylation analysis of human alpha-1-acid glycoprotein offers a great potential for new biomarker discovery

Toma Keser
Dec 29, 2020; 0:RA120.002433v1-mcp.RA120.002433
Research




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Proteome analysis reveals a significant host-specific response in Rhizobium leguminosarum bv viciae endosymbiotic cells

David Durán
Nov 19, 2020; 0:RA120.002276v1-mcp.RA120.002276
Research




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Site-specific contacts enable distinct modes of TRPV1 regulation by the potassium channel Kv{beta}1 subunit [Molecular Biophysics]

Transient receptor potential vanilloid 1 (TRPV1) channel is a multimodal receptor that is responsible for nociceptive, thermal, and mechanical sensations. However, which biomolecular partners specifically interact with TRPV1 remains to be elucidated. Here, we used cDNA library screening of genes from mouse dorsal root ganglia combined with patch-clamp electrophysiology to identify the voltage-gated potassium channel auxiliary subunit Kvβ1 physically interacting with TRPV1 channel and regulating its function. The interaction was validated in situ using endogenous dorsal root ganglia neurons, as well as a recombinant expression model in HEK 293T cells. The presence of Kvβ1 enhanced the expression stability of TRPV1 channels on the plasma membrane and the nociceptive current density. Surprisingly, Kvβ1 interaction also shifted the temperature threshold for TRPV1 thermal activation. Using site-specific mapping, we further revealed that Kvβ1 interacted with the membrane-distal domain and membrane-proximal domain of TRPV1 to regulate its membrane expression and temperature-activation threshold, respectively. Our data therefore suggest that Kvβ1 is a key element in the TRPV1 signaling complex and exerts dual regulatory effects in a site-specific manner.




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AMPK{beta}1 and AMPK{beta}2 define an isoform-specific gene signature in human pluripotent stem cells, differentially mediating cardiac lineage specification [Cell Biology]

AMP-activated protein kinase (AMPK) is a key regulator of energy metabolism that phosphorylates a wide range of proteins to maintain cellular homeostasis. AMPK consists of three subunits: α, β, and γ. AMPKα and β are encoded by two genes, the γ subunit by three genes, all of which are expressed in a tissue-specific manner. It is not fully understood, whether individual isoforms have different functions. Using RNA-Seq technology, we provide evidence that the loss of AMPKβ1 and AMPKβ2 lead to different gene expression profiles in human induced pluripotent stem cells (hiPSCs), indicating isoform-specific function. The knockout of AMPKβ2 was associated with a higher number of differentially regulated genes than the deletion of AMPKβ1, suggesting that AMPKβ2 has a more comprehensive impact on the transcriptome. Bioinformatics analysis identified cell differentiation as one biological function being specifically associated with AMPKβ2. Correspondingly, the two isoforms differentially affected lineage decision toward a cardiac cell fate. Although the lack of PRKAB1 impacted differentiation into cardiomyocytes only at late stages of cardiac maturation, the availability of PRKAB2 was indispensable for mesoderm specification as shown by gene expression analysis and histochemical staining for cardiac lineage markers such as cTnT, GATA4, and NKX2.5. Ultimately, the lack of AMPKβ1 impairs, whereas deficiency of AMPKβ2 abrogates differentiation into cardiomyocytes. Finally, we demonstrate that AMPK affects cellular physiology by engaging in the regulation of hiPSC transcription in an isoform-specific manner, providing the basis for further investigations elucidating the role of dedicated AMPK subunits in the modulation of gene expression.




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Depletion of essential isoprenoids and ER stress induction following acute liver-specific deletion of HMG-CoA reductase

Marco De Giorgi
Dec 1, 2020; 61:1675-1686
Research Articles




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Depletion of essential isoprenoids and ER stress induction following acute liver-specific deletion of HMG-CoA reductase [Research Articles]

HMG-CoA reductase (Hmgcr) is the rate-limiting enzyme in the mevalonate pathway and is inhibited by statins. In addition to cholesterol, Hmgcr activity is also required for synthesizing nonsterol isoprenoids, such as dolichol, ubiquinone, and farnesylated and geranylgeranylated proteins. Here, we investigated the effects of Hmgcr inhibition on nonsterol isoprenoids in the liver. We have generated new genetic models to acutely delete genes in the mevalonate pathway in the liver using AAV-mediated delivery of Cre-recombinase (AAV-Cre) or CRISPR/Cas9 (AAV-CRISPR). The genetic deletion of Hmgcr by AAV-Cre resulted in extensive hepatocyte apoptosis and compensatory liver regeneration. At the biochemical level, we observed decreased levels of sterols and depletion of the nonsterol isoprenoids, dolichol and ubiquinone. At the cellular level, Hmgcr-null hepatocytes showed ER stress and impaired N-glycosylation. We further hypothesized that the depletion of dolichol, essential for N-glycosylation, could be responsible for ER stress. Using AAV-CRISPR, we somatically disrupted dehydrodolichyl diphosphate synthase subunit (Dhdds), encoding a branch point enzyme required for dolichol biosynthesis. Dhdds-null livers showed ER stress and impaired N-glycosylation, along with apoptosis and regeneration. Finally, the combined deletion of Hmgcr and Dhdds synergistically exacerbated hepatocyte ER stress. Our data show a critical role for mevalonate-derived dolichol in the liver and suggest that dolichol depletion is at least partially responsible for ER stress and apoptosis upon potent Hmgcr inhibition.




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Cutting out the fat: Site-specific deacylation of an ion channel [Membrane Biology]

S-Acylation, a reversible post-translational lipid modification of proteins, controls the properties and function of various proteins, including ion channels. Large conductance Ca2+-activated potassium (BK) channels are S-acylated at two sites that impart distinct functional effects. Whereas the enzymes that attach lipid groups are known, the enzymes mediating lipid removal (i.e. deacylation) are largely unknown. Here, McClafferty et al. identify two enzymes, ABHD17a and ABHD17c, that excise BK channel lipid groups with remarkable precision. These findings lend insights into mechanisms that orchestrate the (de)acylation that fine-tunes ion channel function in physiology and disease.




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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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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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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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Depolarization-dependent Induction of Site-specific Changes in Sialylation on N-linked Glycoproteins in Rat Nerve Terminals [Research]

Synaptic transmission leading to release of neurotransmitters in the nervous system is a fast and highly dynamic process. Previously, protein interaction and phosphorylation have been thought to be the main regulators of synaptic transmission. Here we show that sialylation of N-linked glycosylation is a novel potential modulator of neurotransmitter release mechanisms by investigating depolarization-dependent changes of formerly sialylated N-linked glycopeptides. We suggest that negatively charged sialic acids can be modulated, similarly to phosphorylation, by the action of sialyltransferases and sialidases thereby changing local structure and function of membrane glycoproteins. We characterized site-specific alteration in sialylation on N-linked glycoproteins in isolated rat nerve terminals after brief depolarization using quantitative sialiomics. We identified 1965 formerly sialylated N-linked glycosites in synaptic proteins and found that the abundances of 430 glycosites changed after 5 s depolarization. We observed changes on essential synaptic proteins such as synaptic vesicle proteins, ion channels and transporters, neurotransmitter receptors and cell adhesion molecules. This study is to our knowledge the first to describe ultra-fast site-specific modulation of the sialiome after brief stimulation of a biological system.




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Site-specific N-glycosylation Characterization of Recombinant SARS-CoV-2 Spike Proteins [Research]

The glycoprotein spike (S) on the surface of SARS-CoV-2 is a determinant for viral invasion and host immune response. Herein, we characterized the site-specific N-glycosylation of S protein at the level of intact glycopeptides. All 22 potential N-glycosites were identified in the S-protein protomer and were found to be preserved among the 753 SARS-CoV-2 genome sequences. The glycosites exhibited glycoform heterogeneity as expected for a human cell-expressed protein subunit. We identified masses that correspond to 157 N-glycans, primarily of the complex type. In contrast, the insect cell-expressed S protein contained 38 N-glycans, completely of the high-mannose type. Our results revealed that the glycan types were highly determined by the differential processing of N-glycans among human and insect cells, regardless of the glycosites’ location. Moreover, the N-glycan compositions were conserved among different sizes of subunits. Our study indicate that the S protein N-glycosylation occurs regularly at each site, albeit the occupied N-glycans were diverse and heterogenous. This N-glycosylation landscape and the differential N-glycan patterns among distinct host cells are expected to shed light on the infection mechanism and present a positive view for the development of vaccines and targeted drugs.




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Proteome analysis reveals a significant host-specific response in Rhizobium leguminosarum bv viciae endosymbiotic cells [Research]

The Rhizobium-legume symbiosis is a beneficial interaction in which the bacterium converts atmospheric nitrogen into ammonia and delivers it to the plant in exchange for carbon compounds. This symbiosis implies the adaptation of bacteria to live inside host plant cells. In this work we apply RP-LC-MS/MS and  iTRAQ techniques to study the proteomic profile of endosymbiotic cells (bacteroids) induced by Rhizobium leguminosarum bv viciae strain UPM791 in legume nodules. Nitrogenase subunits, tricarboxylic acid cycle enzymes, and stress response proteins are amongst the most abundant from over one thousand rhizobial proteins identified in pea (Pisum sativum) bacteroids. Comparative analysis of bacteroids induced in pea and in lentil (Lens culinaris)nodules revealed the existence of a significant host-specific differential response affecting dozens of bacterial proteins, including stress-related proteins, transcriptional regulators, and proteins involved in the carbon and nitrogen metabolisms. A mutant affected in one of these proteins, homologous to a GntR-like transcriptional regulator, showed a symbiotic performance significantly  impaired in symbiosis with pea, but not with lentil plants. Analysis of the proteomes of bacteroids isolated from both hosts also revealed the presence of different sets of plant-derived nodule-specific cysteine rich (NCR) peptides, indicating that the endosymbiotic bacteria find a host-specific cocktail of chemical stressors inside the nodule. By studying variations of the bacterial response to different plant cell environments we will be able to identify specific limitations imposed by the host that might give us clues for the improvement of rhizobial performance.




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High-throughput and site-specific N-glycosylation analysis of human alpha-1-acid glycoprotein offers a great potential for new biomarker discovery [Research]

Alpha-1-acid glycoprotein (AGP) is an acute phase glycoprotein in blood, which is primarily synthetized in the liver and whose biological role is not completely understood. It consists of 45% carbohydrates that are present in the form of five N-linked complex glycans. AGP N-glycosylation was shown to be changed in many different diseases and some changes appear to be disease-specific, thus it has a great diagnostic and prognostic potential. However, AGP glycosylation was mainly analyzed in small cohorts and without detailed site-specific glycan information. Here, we developed a cost-effective method for a high-throughput and site-specific N-glycosylation LC-MS analysis of AGP which can be applied on large cohorts, aid in search for novel disease biomarkers and enable better understanding of AGP’s role and function in health and disease. The method does not require isolation of AGP with antibodies and affinity chromatography, but AGP is enriched by acid precipitation from 5 μl of bloodplasma in a 96 well format. After trypsinization, AGP glycopeptides are purified using a hydrophilic interaction chromatography based solid-phase extraction and analyzed by RP-LC-ESI-MS. We used our method to show for the first time that AGP N-glycan profile is stable in healthy individuals (14 individuals in 3 time points), which is a requirement for evaluation of its diagnostic potential. Furthermore, we tested our method on a population including individuals with registered hyperglycemia in critical illness (59 cases and 49 controls), which represents a significantly increased risk of developing type 2 diabetes. Individuals at higher risk of diabetes presented increased N-glycan branching on AGP’s second glycosylation site and lower sialylation of N-glycans on AGP’s third and AGP1’s fourth glycosylation site. Although this should be confirmed on a larger prospective cohort, it indicates that site-specific AGP N-glycan profile could help distinguish individuals who are at risk of type 2 diabetes.




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Nonspecific DNA binding by P1 ParA determines the distribution of plasmid partition and repressor activities [Microbiology]

The faithful segregation, or “partition,” of many low-copy number bacterial plasmids is driven by plasmid-encoded ATPases that are represented by the P1 plasmid ParA protein. ParA binds to the bacterial nucleoid via an ATP-dependent nonspecific DNA (nsDNA)-binding activity, which is essential for partition. ParA also has a site-specific DNA-binding activity to the par operator (parOP), which requires either ATP or ADP, and which is essential for it to act as a transcriptional repressor but is dispensable for partition. Here we examine how DNA binding by ParA contributes to the relative distribution of its plasmid partition and repressor activities, using a ParA with an alanine substitution at Arg351, a residue previously predicted to participate in site-specific DNA binding. In vivo, the parAR351A allele is compromised for partition, but its repressor activity is dramatically improved so that it behaves as a “super-repressor.” In vitro, ParAR351A binds and hydrolyzes ATP, and undergoes a specific conformational change required for nsDNA binding, but its nsDNA-binding activity is significantly damaged. This defect in turn significantly reduces the assembly and stability of partition complexes formed by the interaction of ParA with ParB, the centromere-binding protein, and DNA. In contrast, the R351A change shows only a mild defect in site-specific DNA binding. We conclude that the partition defect is due to altered nsDNA binding kinetics and affinity for the bacterial chromosome. Furthermore, the super-repressor phenotype is explained by an increased pool of non-nucleoid bound ParA that is competent to bind parOP and repress transcription.




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Correction: Transcriptional factors Smad1 and Smad9 act redundantly to mediate zebrafish ventral specification downstream of Smad5. [Additions and Corrections]

VOLUME 289 (2014) PAGES 6604–6618In Fig. 4G, in the foxi1 panel, the images in Fig. 4G, i and l, corresponding to “smad1 MO” and “smad5 MO + samd1/9 mRNA” samples, respectively, were inadvertently reused during figure preparation. This error has now been corrected using images pertaining to each treatment and sample. This correction does not affect the results or conclusions of the work.jbc;295/52/18650/F4F1F4Figure 4G.




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Nuclear Imaging of Bispecific Antibodies on the Rise

Bispecific antibodies (bsAbs) are engineered to target 2 different epitopes simultaneously. About 75% of the 16 clinically approved bsAbs have entered the clinic internationally since 2022. Hence, research on biomedical imaging of various radiolabeled bsAb scaffolds may serve to improve patient selection for bsAb therapy. Here, we provide a comprehensive overview of recent advances in radiolabeled bsAbs for imaging via PET or SPECT. We compare direct targeting and pretargeting approaches in preclinical and clinical studies in oncologic research. Furthermore, we show preclinical applications of imaging bsAbs in neurodegenerative diseases. Finally, we offer perspectives on the future directions of imaging bsAbs based on their challenges and opportunities.




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Atp13a5 Marker Reveals Pericyte Specification in the Mouse Central Nervous System

Xinying Guo
Oct 23, 2024; 44:e0727242024-e0727242024
Cellular




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Targeting Cre Recombinase to Specific Neuron Populations with Bacterial Artificial Chromosome Constructs

Shiaoching Gong
Sep 12, 2007; 27:9817-9823
Toolbox




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TRIM46 Is Required for Microtubule Fasciculation In Vivo But Not Axon Specification or Axon Initial Segment Formation

Vertebrate nervous systems use the axon initial segment (AIS) to initiate action potentials and maintain neuronal polarity. The microtubule-associated protein tripartite motif containing 46 (TRIM46) was reported to regulate axon specification, AIS assembly, and neuronal polarity through the bundling, or fasciculation, of microtubules in the proximal axon. However, these claims are based on TRIM46 knockdown in cultured neurons. To investigate TRIM46 function in vivo, we examined male and female TRIM46 knock-out mice. Contrary to previous reports, we find that TRIM46 is dispensable for axon specification and AIS formation. TRIM46 knock-out mice are viable, have normal behavior, and have normal brain structure. Thus, TRIM46 is not required for AIS formation, axon specification, or nervous system function. However, we confirm that TRIM46 is required for microtubule fasciculation. We also show TRIM46 enrichment in the first ~100 μm of axon occurs independently of ankyrinG (AnkG) in vivo, although AnkG is required to restrict TRIM46 only to the AIS. Our results highlight the need for further investigation of the mechanisms by which the AIS and microtubules interact to shape neuronal structure and function.




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Atp13a5 Marker Reveals Pericyte Specification in the Mouse Central Nervous System

Perivascular mural cells including vascular smooth cells (VSMCs) and pericytes are integral components of the vascular system. In the central nervous system (CNS), pericytes are also indispensable for the blood–brain barrier (BBB), blood–spinal cord barrier, and blood–retinal barrier and play key roles in maintaining cerebrovascular and neuronal functions. However, the functional specifications of pericytes between CNS and peripheral organs have not been resolved at the genetic and molecular levels. Hence, the generation of reliable CNS pericyte-specific models and genetic tools remains very challenging. Here, we report a new CNS pericyte marker in mice. This putative cation-transporting ATPase 13A5 (Atp13a5) marker was identified through single-cell transcriptomics, based on its specificity to brain pericytes. We further generated a knock-in model with both tdTomato reporter and Cre recombinase. Using this model to trace the distribution of Atp13a5-positive pericytes in mice, we found that the tdTomato reporter reliably labels the CNS pericytes, including the ones in spinal cord and retina but not peripheral organs. Interestingly, brain pericytes are likely shaped by the developing neural environment, as Atp13a5-positive pericytes start to appear around murine embryonic day 15 (E15) and expand along the cerebrovasculature. Thus, Atp13a5 is a specific marker of CNS pericyte lineage, and this Atp13a5-based model is a reliable tool to explore the heterogeneity of pericytes and BBB functions in health and diseases.




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Neural Representations of Concreteness and Concrete Concepts Are Specific to the Individual

Different people listening to the same story may converge upon a largely shared interpretation while still developing idiosyncratic experiences atop that shared foundation. What linguistic properties support this individualized experience of natural language? Here, we investigate how the "concrete–abstract" axis—the extent to which a word is grounded in sensory experience—relates to within- and across-subject variability in the neural representations of language. Leveraging a dataset of human participants of both sexes who each listened to four auditory stories while undergoing functional magnetic resonance imaging, we demonstrate that neural representations of "concreteness" are both reliable across stories and relatively unique to individuals, while neural representations of "abstractness" are variable both within individuals and across the population. Using natural language processing tools, we show that concrete words exhibit similar neural representations despite spanning larger distances within a high-dimensional semantic space, which potentially reflects an underlying representational signature of sensory experience—namely, imageability—shared by concrete words but absent from abstract words. Our findings situate the concrete–abstract axis as a core dimension that supports both shared and individualized representations of natural language.




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Pre- and Postsynaptic MEF2C Promotes Experience-Dependent, Input-Specific Development of Cortical Layer 4 to Layer 2/3 Excitatory Synapses and Regulates Activity-Dependent Expression of Synaptic Cell Adhesion Molecules

Experience- and activity-dependent transcription is a candidate mechanism to mediate development and refinement of specific cortical circuits. Here, we demonstrate that the activity-dependent transcription factor myocyte enhancer factor 2C (MEF2C) is required in both presynaptic layer (L) 4 and postsynaptic L2/3 mouse (male and female) somatosensory (S1) cortical neurons for development of this specific synaptic connection. While postsynaptic deletion of Mef2c weakens L4 synaptic inputs, it has no effect on inputs from local L2/3, contralateral S1, or the ipsilateral frontal/motor cortex. Similarly, homozygous or heterozygous deletion of Mef2c in presynaptic L4 neurons weakens L4 to L2/3 excitatory synaptic inputs by decreasing presynaptic release probability. Postsynaptic MEF2C is specifically required during an early postnatal, experience-dependent, period for L4 to L2/3 synapse function, and expression of transcriptionally active MEF2C (MEF2C-VP16) rescues weak L4 to L2/3 synaptic strength in sensory-deprived mice. Together, these results suggest that experience- and/or activity-dependent transcriptional activation of MEF2C promotes development of L4 to L2/3 synapses. Additionally, MEF2C regulates the expression of many pre- and postsynaptic genes in postnatal cortical neurons. Interestingly, MEF2C was necessary for activity-dependent expression of many presynaptic genes, including those that function in transsynaptic adhesion and neurotransmitter release. This work provides mechanistic insight into the experience-dependent development of specific cortical circuits.






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Vivo Y300 India Launch Timeline, Colour Options, Specifications Tipped

Vivo Y300 Plus with Snapdragon 695 SoC was launched in India last month. According to a report, Vivo is also readying to launch the Y300 in the country. Colourways and specifications of the upcoming Vivo Y series phone have also leaked alongside its India launch timeline. It is said to be available in three colour options. The Vivo Y300 could boast a Sony IMX882 portrait camera.




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Vivo Y18t With 5,000mAh Battery, Unisoc T612 Chipset Launched in India: Price, Specifications

Vivo Y18t was silently launched in India as the latest entrant in the company's Y series. The new Vivo handset arrives in two colourways with an IP54-rated build. The Vivo Y18t sports a dual rear camera unit led by a 50-megapixel primary sensor. It runs on a Unisoc T612 chipset with 4GB RAM and 128GB storage. The budget smartphone carries a 5,000mAh battery with 15W fast charging support.




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Oppo Pad 3 Specifications Tipped; Said to Get 144Hz Display, Dimensity SoC, SuperVOOC Charging, More

Following the launch of Oppo's Pad 3 Pro tablet, which boasted premium hardware, a new leak has surfaced online that indicates the existence of a lower-priced Pad 3 with watered-down specifications. Leaked details suggests that the mid-range tablet has specifications similar to the older OnePlus Pad, which was unveiled in the first half of 2023. Te upcoming tablet is said to get a MediaTek Dimensity SoC, an 11.6-inch display, and a 9,510mAh battery.




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Constraining some nets to route through a specific metal layer, and changing some pin/cell placements and wire directions in Cadence Innovus.

Hello All:

I am looking for help on the following, as I am new to Cadence tools [I have to use Cadence Innovus for Physical Design after Logic Synthesis using Synopsys Design Compiler, using Nangate 45 nm Open Cell Library]: while using Cadence Innovus, I would need to select a few specific nets to be routed through a specific metal layer. How can I do this on Innovus [are there any command(s)]? Also, would writing and sourcing a .tcl script [containing the command(s)] on the Innovus terminal after the Placement Stage of Physical Design be fine for this?

Secondly, is there a way in Innovus to manipulate layout components, such as changing some pin placements, wire directions (say for example, wire direction changed to facing east from west, etc.) or moving specific closely placed cells around (without violating timing constraints of course) using any command(s)/.tcl script? If so, would pin placement changes and constraining some closely placed cells to be moved apart be done after Floorplanning/Powerplanning (that is, prior to Placement) and the wire direction changes be done after Routing? 

While making the necessary changes, could I use the usual Innovus commands to perform Physical Design of the remaining nets/wires/pins/cells, etc., or would anything need modification for the remaining components as well?

I would finally need to dump the entire design containing all of this in a .def file.

I tried looking up but could only find matter on Virtuoso and SKILL scripting, but I'd be using Innovus GUI/terminal with Nangate 45 nm Open Cell Library. I know this is a lot, but I would greatly appreciate your help. Thanks in advance.

Riya




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Using vManager to identify line coverage from a specific test

I have been using the rank feature to identify tests that are redundant in our environment, but then I realized I'd also like to be able to see exactly what coverage goes into increasing the delta_cov value for a given test. If I had a test in my rank report that contributed 0.5% of the delta_cov, how could I got about seeing exactly where that 0.5% was coming from? It seems like that might be part of the correlate function, but I couldn't mange to find a way to see what specific coverage was being contributed for a given test.




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What Can You Eat on the Specific Carbohydrate Diet (SCD)?

Title: What Can You Eat on the Specific Carbohydrate Diet (SCD)?
Category: Health and Living
Created: 8/24/2022 12:00:00 AM
Last Editorial Review: 8/24/2022 12:00:00 AM




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Pfizer Asks FDA to Approve Omicron-Specific Booster Shot

Title: Pfizer Asks FDA to Approve Omicron-Specific Booster Shot
Category: Health News
Created: 8/22/2022 12:00:00 AM
Last Editorial Review: 8/23/2022 12:00:00 AM




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A germline PAF1 paralog complex ensures cell type-specific gene expression [Research Papers]

Animal germline development and fertility rely on paralogs of general transcription factors that recruit RNA polymerase II to ensure cell type-specific gene expression. It remains unclear whether gene expression processes downstream from such paralog-based transcription is distinct from that of canonical RNA polymerase II genes. In Drosophila, the testis-specific TBP-associated factors (tTAFs) activate over a thousand spermatocyte-specific gene promoters to enable meiosis and germ cell differentiation. Here, we show that efficient termination of tTAF-activated transcription relies on testis-specific paralogs of canonical polymerase-associated factor 1 complex (PAF1C) proteins, which form a testis-specific PAF1C (tPAF). Consequently, tPAF mutants show aberrant expression of hundreds of downstream genes due to read-in transcription. Furthermore, tPAF facilitates expression of Y-linked male fertility factor genes and thus serves to maintain spermatocyte-specific gene expression. Consistently, tPAF is required for the segregation of meiotic chromosomes and male fertility. Supported by comparative in vivo protein interaction assays, we provide a mechanistic model for the functional divergence of tPAF and the PAF1C and identify transcription termination as a developmentally regulated process required for germline-specific gene expression.




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Consolidating roles of neuroimmune reflexes: specificity of afferent, central, and efferent signals in homeostatic immune networks [Special Section: Symposium Outlook]

Neural reflexes occupy a central role in physiological homeostasis. The vagus nerve is a major conduit for transmitting afferent and efferent signals in homeostatic reflex arcs between the body and the brain. Recent advances in neuroscience, immunology, and physiology have revealed important vagus nerve mechanisms in suppressing inflammation and treating rheumatoid arthritis and other autoimmune conditions. Numerous clinical trials indicate that there is significant benefit to vagus nerve stimulation therapy. Although many questions are still unanswered, it will be important, even necessary, to pursue answers that will be useful in guiding interventions to modulate immunological and physiological homeostasis.




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High-resolution reconstruction of a C. elegans ribosome sheds light on evolutionary dynamics and tissue specificity [ARTICLE]

Caenorhabditis elegans is an important model organism for human health and disease, with foundational contributions to the understanding of gene expression and tissue patterning in animals. An invaluable tool in modern gene expression research is the presence of a high-resolution ribosome structure, though no such structure exists for C. elegans. Here, we present a high-resolution single-particle cryogenic electron microscopy (cryo-EM) reconstruction and molecular model of a C. elegans ribosome, revealing a significantly streamlined animal ribosome. Many facets of ribosome structure are conserved in C. elegans, including overall ribosomal architecture and the mechanism of cycloheximide, whereas other facets, such as expansion segments and eL28, are rapidly evolving. We identify uL5 and uL23 as two instances of tissue-specific ribosomal protein paralog expression conserved in Caenorhabditis, suggesting that C. elegans ribosomes vary across tissues. The C. elegans ribosome structure will provide a basis for future structural, biochemical, and genetic studies of translation in this important animal system.




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Chronic Administration of Cannabinoid Agonists ACEA, AM1241, and CP55,940 Induce Sex-Specific Differences in Tolerance and Sex Hormone Changes in a Chemotherapy-Induced Peripheral Neuropathy [Special Section: Cannabinoid Signaling in Human Health and Dise

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of chemotherapy treatment, routinely manifesting as increased pain sensitivity (allodynia) in distal extremities. Despite its prevalence, effective treatment options are limited. Cannabinoids are increasingly being evaluated for their ability to treat chronic pain conditions, including CIPN. While previous studies have revealed sex differences in cannabinoid-mediated antinociception in acute and chronic pain models, there is a paucity of studies addressing potential sex differences in the response of CIPN to cannabinoid treatment. Therefore, we evaluated the long-term antiallodynic efficacy of cannabinoid receptor type 1 (CB1)-selective, cannabinoid receptor type 2 (CB2)-selective, and CB1/CB2 mixed agonists in the cisplatin CIPN model, using both male and female mice. CB1 selective agonism was observed to have sex differences in the development of tolerance to antiallodynic effects, with females developing tolerance more rapidly than males, while the antiallodynic effects of selective CB2 agonism lacked tolerance development. Compound-specific changes to the female estrous cycle and female plasma estradiol levels were noted, with CB1 selective agonism decreasing plasma estradiol while CB2 selective agonism increased plasma estradiol. Chronic administration of a mixed CB1/CB2 agonist resulted in increased mRNA expression of proinflammatory cytokines and endocannabinoid regulatory enzymes in female spinal cord tissue. Ovarian tissue was noted to have proinflammatory cytokine mRNA expression following administration of a CB2 acting compound while selective CB1 agonism resulted in decreased proinflammatory cytokines and endocannabinoid regulatory enzymes in testes. These results support the need for further investigation into the role of sex and sex hormones signaling in pain and cannabinoid-mediated antinociceptive effects.

SIGNIFICANCE STATEMENT

CIPN is a common side effect of chemotherapy. We have found that both CB1 and CB2 receptor agonism produce antinociceptive effects in a cisplatin CIPN model. We observed that tolerance to CB1-mediated antinociception developed faster in females and did not develop for CB2-mediated antinociception. Additionally, we found contrasting roles for CB1/CB2 receptors in the regulation of plasma estradiol in females, with CB1 agonism attenuating estradiol and CB2 agonism enhancing estradiol. These findings support the exploration of cannabinoid agonists for CIPN.




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Association of Free-to-Total PSA Ratio and 18F-DCFPyL Prostate-Specific Membrane Antigen PET/CT Findings in Patients with Biochemical Recurrence After Radical Prostatectomy: A Prospective Single-Center Study

In Canada and across the globe, access to PSMA PET/CT is limited and expensive. For patients with biochemical recurrence (BCR) after treatment for prostate cancer, novel strategies are needed to better stratify patients who may or may not benefit from a PSMA PET scan. The role of the free-to-total prostate-specific antigen (PSA) ratio (FPSAR) in posttreatment prostate cancer, specifically in the PSMA PET/CT era, remains unknown. Our aim in this study was to determine the association of FPSAR in patients referred for 18F-DCFPyL PSMA PET/CT in the BCR setting and assess the correlation between FPSAR and 18F-DCFPyL PSMA PET/CT positivity (local recurrence or distant metastases). Methods: This prospective study included 137 patients who were referred for 18F-DCFPyL PSMA PET/CT and had BCR with a total PSA of less than 1 ng/mL after radical prostatectomy (RP) (including adjuvant or salvage radiotherapy). Blood samples were collected on the day of 18F-DCFPyL PSMA PET/CT. FPSAR was categorized as less than 0.10 or as 0.10 or more. A positive 18F-DCFPyL PSMA PET/CT scan was defined by a PROMISE classification lesion score of 2 or 3, irrespective of the site of increased tracer uptake (e.g., prostate, pelvic nodes, bone, or viscera). Results: Overall, 137 blood samples of patients with BCR after RP were analyzed to calculate FPSAR. The median age at 18F-DCFPyL PSMA PET/CT was 68.6 y (interquartile range, 63.0–72.4 y), and the median PSA at 18F-DCFPyL PSMA PET/CT was 0.3 ng/mL (interquartile range, 0.3–0.6 ng/mL). Eighty-six patients (62.8%) had an FPSAR of less than 0.10, whereas 51 patients (37.2%) had an FPSAR of 0.10 or more. An FPSAR of 0.10 or more was identified as an independent predictor of a positive 18F-DCFPyL PSMA PET/CT scan, with an odds ratio of 6.99 (95% CI, 2.96–16.51; P < 0.001). Conclusion: An FPSAR of 0.10 or more after RP independently correlated with increased odds of a positive 18F-DCFPyL PSMA PET/CT scan among BCR post-RP patients. These findings may offer an inexpensive method by which to triage access to 18F-DCFPyL PSMA PET/CT in jurisdictions where availability is not replete.




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Science needs specific, informed, productive criticism

Professor Dave demolishes Sabine Hossenfelder. I feel that. The topic of my history class last week and this week is about bias in late 19th/early 20th century evolutionary biology, and how we have to be critical and responsible in our assessment of scientific claims. It’s tough, because I’m strongly pro-science (obviously, I hope?) but I […]




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Specific Diabetic Drug is Now Safe for Cancer Patients With Kidney Concerns

Contrary to concerns, GLP-1RA medications don't appear to elevate AKI risk in patients undergoing cancer treatment.




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BioSpecifics Technologies Corp. Reports First Quarter 2010 Financial Results

BioSpecifics Technologies Corp. Reports First Quarter 2010 Financial Results




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iQOO 13 Launch Date in India Confirmed for December 3: Check Expected Price and Full Specifications

The iQOO 13 recently got an official launch date in India. To recall, the iQOO 13 made its debut in China last week as the second smartphone to use the Snapdragon 8 Elite chipset. However, no official launch date for the




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ASUS ROG Phone 9 Series Rumor Roundup: Check Expected Price, Release Date, Specifications, Design, More

As we inch closer to the ASUS ROG Phone 9 series launch on November 19, there's a growing buzz around what this latest addition to ASUS's gaming smartphone lineup will bring. With rumors swirling about some interesting upgrades, here's a look




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Vivo Launches New Entry-Level Smartphone in its Y Series in India: Check Price and Specifications

Vivo has officially unveiled a new entry-level smartphone in India. The Vivo Y18t price in India is set at Rs 9,499 for the sole 4GB/128GB model. The Vivo Y18t is now available for purchase through the Vivo India e-store and Flipkart.




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Asus SmartO MD200 Launched in India for Rs 2,499: Check Features, Specifications

Asus has introduced the SmartO MD200 Mouse in India, marking a significant addition to its lineup of computer accessories. This latest offering is designed to blend seamlessly with the user's work environment, enhancing both productivity and style. Available in two colors,




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Apple Launches iMac with M4 Chip and Apple Intelligence in India: Check Price, Specifications, Availability

Apple has unveiled its latest iMac, featuring the M4 chip and Apple Intelligence. This new model offers substantial performance enhancements and innovative features within a sleek design. The M4 chip boosts speed by up to 1.7 times for everyday tasks and




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Apple M4 Pro, M4 Max Chips Announced with Thunderbolt 5 and Improved Performance: Features, Specifications

Apple has introduced the M4 Pro and M4 Max chips, expanding its silicon lineup alongside the M4. These processors are crafted using advanced second-generation 3-nanometer technology, enhancing both performance and energy efficiency. The M4 series boasts the fastest CPU core globally,




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Government to finalize specific bankruptcy settlement for MSMEs under IBC

Under section 240A of the Insolvency and Bankruptcy Code (IBC), 2016, the Ministry of Corporate Affairs (MCA) is finalizing a specific insolvency resolution. "The Ministry of Corporate Affairs is finalizing a particular bankruptcy settlement under section 240A of the Code to




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EICMA 2024: Aprilia Tuono 457 Key Features & Specifications

Aprilia has introduced the Tuono 457, a naked version of the RS 457 sportbike. This new model retains many features from its predecessor, including the engine, frame, and electronics. However, it sports a redesigned headlight and offers a more upright riding




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Vibrational analysis of auranofin complexes with cysteine and selenocysteine unveils distinct binding motifs and specific unimolecular reactivity

Inorg. Chem. Front., 2024, Advance Article
DOI: 10.1039/D4QI02023E, Research Article
Open Access
  This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Roberto Paciotti, Davide Corinti, Cecilia Coletti, Nazzareno Re, Giel Berden, Jos Oomens, Simonetta Fornarini, Maria Elisa Crestoni
The [(Et3P)AuCys]+ and [(Et3P)AuSec]+ ions and their deamination products were characterized using IRMPD spectroscopy backed by DFT calculations finding differences in binding motifs and reactivity.
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