it The Mechanism of NEDD8 Activation of CUL5 Ubiquitin E3 Ligases By www.mcponline.org Published On :: 2020-12-02 Ryan J LumpkinDec 2, 2020; 0:RA120.002414v1-mcp.RA120.002414Research Full Article
it Peptidomics-driven strategy reveals peptides and predicted proteases associated with oral cancer prognosis By www.mcponline.org Published On :: 2020-11-11 Leandro Xavier NevesNov 11, 2020; 0:RA120.002227v1-mcp.RA120.002227Research Full Article
it Spatially Resolved Activity-based Proteomic Profiles of the Murine Small Intestinal Lipases By www.mcponline.org Published On :: 2020-12-01 Matthias SchittmayerDec 1, 2020; 19:2104-2114Research Full Article
it Proteomic identification of Coxiella burnetii effector proteins targeted to the host cell mitochondria during infection By www.mcponline.org Published On :: 2020-11-11 Laura F FieldenNov 11, 2020; 0:RA120.002370v1-mcp.RA120.002370Research Full Article
it Protein modification characteristics of the malaria parasite Plasmodium falciparum and the infected erythrocytes By www.mcponline.org Published On :: 2020-11-04 Jianhua WangNov 4, 2020; 0:RA120.002375v1-mcp.RA120.002375Research Full Article
it Plasma proteomic data can contain personally identifiable, sensitive information and incidental findings By www.mcponline.org Published On :: 2020-12-17 Philipp Emanuel GeyerDec 17, 2020; 0:RA120.002359v1-mcp.RA120.002359Research Full Article
it Secretory galectin-3 induced by glucocorticoid stress triggers stemness exhaustion of hepatic progenitor cells [Signal Transduction] By www.jbc.org Published On :: 2020-12-04T00:06:06-08:00 Adult progenitor cell populations typically exist in a quiescent state within a controlled niche environment. However, various stresses or forms of damage can disrupt this state, which often leads to dysfunction and aging. We built a glucocorticoid (GC)-induced liver damage model of mice, found that GC stress induced liver damage, leading to consequences for progenitor cells expansion. However, the mechanisms by which niche factors cause progenitor cells proliferation are largely unknown. We demonstrate that, within the liver progenitor cells niche, Galectin-3 (Gal-3) is responsible for driving a subset of progenitor cells to break quiescence. We show that GC stress causes aging of the niche, which induces the up-regulation of Gal-3. The increased Gal-3 population increasingly interacts with the progenitor cell marker CD133, which triggers focal adhesion kinase (FAK)/AMP-activated kinase (AMPK) signaling. This results in the loss of quiescence and leads to the eventual stemness exhaustion of progenitor cells. Conversely, blocking Gal-3 with the inhibitor TD139 prevents the loss of stemness and improves liver function. These experiments identify a stress-dependent change in progenitor cell niche that directly influence liver progenitor cell quiescence and function. Full Article
it VBP1 modulates Wnt/{beta}-catenin signaling by mediating the stability of the transcription factors TCF/LEFs [Signal Transduction] By www.jbc.org Published On :: 2020-12-04T00:06:06-08:00 The Wnt/β-catenin pathway is one of the major pathways that regulates embryonic development, adult homeostasis, and stem cell self-renewal. In this pathway, transcription factors T-cell factor and lymphoid enhancer factor (TCF/LEF) serve as a key switch to repress or activate Wnt target gene transcription by recruiting repressor molecules or interacting with the β-catenin effector, respectively. It has become evident that the protein stability of the TCF/LEF family members may play a critical role in controlling the activity of the Wnt/β-catenin signaling pathway. However, factors that regulate the stability of TCF/LEFs remain largely unknown. Here, we report that pVHL binding protein 1 (VBP1) regulates the Wnt/β-catenin signaling pathway by controlling the stability of TCF/LEFs. Surprisingly, we found that either overexpression or knockdown of VBP1 decreased Wnt/β-catenin signaling activity in both cultured cells and zebrafish embryos. Mechanistically, VBP1 directly binds to all four TCF/LEF family members and von Hippel-Lindau tumor-suppressor protein (pVHL). Either overexpression or knockdown of VBP1 increases the association between TCF/LEFs and pVHL and then decreases the protein levels of TCF/LEFs via proteasomal degradation. Together, our results provide mechanistic insights into the roles of VBP1 in controlling TCF/LEFs protein stability and regulating Wnt/β-catenin signaling pathway activity. Full Article
it ERAD deficiency promotes mitochondrial dysfunction and transcriptional rewiring in human hepatic cells [Cell Biology] By www.jbc.org Published On :: 2020-12-04T00:06:05-08:00 Mitochondrial dysfunction is associated with a variety of human diseases including neurodegeneration, diabetes, nonalcohol fatty liver disease (NAFLD), and cancer, but its underlying causes are incompletely understood. Using the human hepatic cell line HepG2 as a model, we show here that endoplasmic reticulum-associated degradation (ERAD), an ER protein quality control process, is critically required for mitochondrial function in mammalian cells. Pharmacological inhibition or genetic ablation of key proteins involved in ERAD increased cell death under both basal conditions and in response to proinflammatory cytokines, a situation frequently found in NAFLD. Decreased viability of ERAD-deficient HepG2 cells was traced to impaired mitochondrial functions including reduced ATP production, enhanced reactive oxygen species (ROS) accumulation, and increased mitochondrial outer membrane permeability. Transcriptome profiling revealed widespread down-regulation of genes underpinning mitochondrial functions, and up-regulation of genes associated with tumor growth and aggression. These results highlight a critical role for ERAD in maintaining mitochondrial functional and structural integrity and raise the possibility of improving cellular and organismal mitochondrial function via enhancing cellular ERAD capacity. Full Article
it Human pancreatic cancer cells under nutrient deprivation are vulnerable to redox system inhibition [Cell Biology] By www.jbc.org Published On :: 2020-12-04T00:06:05-08:00 Large regions in tumor tissues, particularly pancreatic cancer, are hypoxic and nutrient-deprived because of unregulated cell growth and insufficient vascular supply. Certain cancer cells, such as those inside a tumor, can tolerate these severe conditions and survive for prolonged periods. We hypothesized that small molecular agents, which can preferentially reduce cancer cell survival under nutrient-deprived conditions, could function as anticancer drugs. In this study, we constructed a high-throughput screening system to identify such small molecules and screened chemical libraries and microbial culture extracts. We were able to determine that some small molecular compounds, such as penicillic acid, papyracillic acid, and auranofin, exhibit preferential cytotoxicity to human pancreatic cancer cells under nutrient-deprived compared with nutrient-sufficient conditions. Further analysis revealed that these compounds target to redox systems such as GSH and thioredoxin and induce accumulation of reactive oxygen species in nutrient-deprived cancer cells, potentially contributing to apoptosis under nutrient-deprived conditions. Nutrient-deficient cancer cells are often deficient in GSH; thus, they are susceptible to redox system inhibitors. Targeting redox systems might be an attractive therapeutic strategy under nutrient-deprived conditions of the tumor microenvironment. Full Article
it Agonist-activated glucagon receptors are deubiquitinated at early endosomes by two distinct deubiquitinases to facilitate Rab4a-dependent recycling [Signal Transduction] By www.jbc.org Published On :: 2020-12-04T00:06:05-08:00 The glucagon receptor (GCGR) activated by the peptide hormone glucagon is a seven-transmembrane G protein–coupled receptor (GPCR) that regulates blood glucose levels. Ubiquitination influences trafficking and signaling of many GPCRs, but its characterization for the GCGR is lacking. Using endocytic colocalization and ubiquitination assays, we have identified a correlation between the ubiquitination profile and recycling of the GCGR. Our experiments revealed that GCGRs are constitutively ubiquitinated at the cell surface. Glucagon stimulation not only promoted GCGR endocytic trafficking through Rab5a early endosomes and Rab4a recycling endosomes, but also induced rapid deubiquitination of GCGRs. Inhibiting GCGR internalization or disrupting endocytic trafficking prevented agonist-induced deubiquitination of the GCGR. Furthermore, a Rab4a dominant negative (DN) that blocks trafficking at recycling endosomes enabled GCGR deubiquitination, whereas a Rab5a DN that blocks trafficking at early endosomes eliminated agonist-induced GCGR deubiquitination. By down-regulating candidate deubiquitinases that are either linked with GPCR trafficking or localized on endosomes, we identified signal-transducing adaptor molecule–binding protein (STAMBP) and ubiquitin-specific protease 33 (USP33) as cognate deubiquitinases for the GCGR. Our data suggest that USP33 constitutively deubiquitinates the GCGR, whereas both STAMBP and USP33 deubiquitinate agonist-activated GCGRs at early endosomes. A mutant GCGR with all five intracellular lysines altered to arginines remains deubiquitinated and shows augmented trafficking to Rab4a recycling endosomes compared with the WT, thus affirming the role of deubiquitination in GCGR recycling. We conclude that the GCGRs are rapidly deubiquitinated after agonist-activation to facilitate Rab4a-dependent recycling and that USP33 and STAMBP activities are critical for the endocytic recycling of the GCGR. Full Article
it Site-specific contacts enable distinct modes of TRPV1 regulation by the potassium channel Kv{beta}1 subunit [Molecular Biophysics] By www.jbc.org Published On :: 2020-12-11T00:06:21-08:00 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. Full Article
it Visualizing, quantifying, and manipulating mitochondrial DNA in vivo [Methods and Resources] By www.jbc.org Published On :: 2020-12-18T00:06:18-08:00 Mitochondrial DNA (mtDNA) encodes proteins and RNAs that support the functions of mitochondria and thereby numerous physiological processes. Mutations of mtDNA can cause mitochondrial diseases and are implicated in aging. The mtDNA within cells is organized into nucleoids within the mitochondrial matrix, but how mtDNA nucleoids are formed and regulated within cells remains incompletely resolved. Visualization of mtDNA within cells is a powerful means by which mechanistic insight can be gained. Manipulation of the amount and sequence of mtDNA within cells is important experimentally and for developing therapeutic interventions to treat mitochondrial disease. This review details recent developments and opportunities for improvements in the experimental tools and techniques that can be used to visualize, quantify, and manipulate the properties of mtDNA within cells. Full Article
it Wildtype {sigma}1 receptor and the receptor agonist improve ALS-associated mutation-induced insolubility and toxicity [Neurobiology] By www.jbc.org Published On :: 2020-12-18T00:06:18-08:00 Genetic mutations related to ALS, a progressive neurological disease, have been discovered in the gene encoding σ-1 receptor (σ1R). We previously reported that σ1RE102Q elicits toxicity in cells. The σ1R forms oligomeric states that are regulated by ligands. Nevertheless, little is known about the effect of ALS-related mutations on oligomer formation. Here, we transfected NSC-34 cells, a motor neuronal cell line, and HEK293T cells with σ1R-mCherry (mCh), σ1RE102Q-mCh, or nontagged forms to investigate detergent solubility and subcellular distribution using immunocytochemistry and fluorescence recovery after photobleaching. The oligomeric state was determined using crosslinking procedure. σ1Rs were soluble to detergents, whereas the mutants accumulated in the insoluble fraction. Within the soluble fraction, peak distribution of mutants appeared in higher sucrose density fractions. Mutants formed intracellular aggregates that were co-stained with p62, ubiquitin, and phosphorylated pancreatic eukaryotic translation initiation factor-2-α kinase in NSC-34 cells but not in HEK293T cells. The aggregates had significantly lower recovery in fluorescence recovery after photobleaching. Acute treatment with σ1R agonist SA4503 failed to improve recovery, whereas prolonged treatment for 48 h significantly decreased σ1RE102Q-mCh insolubility and inhibited apoptosis. Whereas σ1R-mCh formed monomers and dimers, σ1RE102Q-mCh also formed trimers and tetramers. SA4503 reduced accumulation of the four types in the insoluble fraction and increased monomers in the soluble fraction. The σ1RE102Q insolubility was diminished by σ1R-mCh co-expression. These results suggest that the agonist and WT σ1R modify the detergent insolubility, toxicity, and oligomeric state of σ1RE102Q, which may lead to promising new treatments for σ1R-related ALS. Full Article
it Fibrillar {alpha}-synuclein toxicity depends on functional lysosomes [Cell Biology] By www.jbc.org Published On :: 2020-12-18T00:06:18-08:00 Neurodegeneration in Parkinson's disease (PD) can be recapitulated in animals by administration of α-synuclein preformed fibrils (PFFs) into the brain. However, the mechanism by which these PFFs induce toxicity is unknown. Iron is implicated in PD pathophysiology, so we investigated whether α-synuclein PFFs induce ferroptosis, an iron-dependent cell death pathway. A range of ferroptosis inhibitors were added to a striatal neuron-derived cell line (STHdhQ7/7 cells), a dopaminergic neuron–derived cell line (SN4741 cells), and WT primary cortical neurons, all of which had been intoxicated with α-synuclein PFFs. Viability was not recovered by these inhibitors except for liproxstatin-1, a best-in-class ferroptosis inhibitor, when used at high doses. High-dose liproxstatin-1 visibly enlarged the area of a cell that contained acidic vesicles and elevated the expression of several proteins associated with the autophagy-lysosomal pathway similarly to the known lysosomal inhibitors, chloroquine and bafilomycin A1. Consistent with high-dose liproxstatin-1 protecting via a lysosomal mechanism, we further de-monstrated that loss of viability induced by α-synuclein PFFs was attenuated by chloroquine and bafilomycin A1 as well as the lysosomal cysteine protease inhibitors, leupeptin, E-64D, and Ca-074-Me, but not other autophagy or lysosomal enzyme inhibitors. We confirmed using immunofluorescence microscopy that heparin prevented uptake of α-synuclein PFFs into cells but that chloroquine did not stop α-synuclein uptake into lysosomes despite impairing lysosomal function and inhibiting α-synuclein toxicity. Together, these data suggested that α-synuclein PFFs are toxic in functional lysosomes in vitro. Therapeutic strategies that prevent α-synuclein fibril uptake into lysosomes may be of benefit in PD. Full Article
it PTPN2 regulates the activation of KRAS and plays a critical role in proliferation and survival of KRAS-driven cancer cells [Signal Transduction] By www.jbc.org Published On :: 2020-12-25T00:06:31-08:00 RAS genes are the most commonly mutated in human cancers and play critical roles in tumor initiation, progression, and drug resistance. Identification of targets that block RAS signaling is pivotal to develop therapies for RAS-related cancer. As RAS translocation to the plasma membrane (PM) is essential for its effective signal transduction, we devised a high-content screening assay to search for genes regulating KRAS membrane association. We found that the tyrosine phosphatase PTPN2 regulates the plasma membrane localization of KRAS. Knockdown of PTPN2 reduced the proliferation and promoted apoptosis in KRAS-dependent cancer cells, but not in KRAS-independent cells. Mechanistically, PTPN2 negatively regulates tyrosine phosphorylation of KRAS, which, in turn, affects the activation KRAS and its downstream signaling. Consistently, analysis of the TCGA database demonstrates that high expression of PTPN2 is significantly associated with poor prognosis of patients with KRAS-mutant pancreatic adenocarcinoma. These results indicate that PTPN2 is a key regulator of KRAS and may serve as a new target for therapy of KRAS-driven cancer. Full Article
it Distant coupling between RNA editing and alternative splicing of the osmosensitive cation channel Tmem63b [Cell Biology] By www.jbc.org Published On :: 2020-12-25T00:06:30-08:00 Post-transcriptional modifications of pre-mRNAs expand the diversity of proteomes in higher eukaryotes. In the brain, these modifications diversify the functional output of many critical neuronal signal molecules. In this study, we identified a brain-specific A-to-I RNA editing that changed glutamine to arginine (Q/R) at exon 20 and an alternative splicing of exon 4 in Tmem63b, which encodes a ubiquitously expressed osmosensitive cation channel. The channel isoforms lacking exon 4 occurred in ∼80% of Tmem63b mRNAs in the brain but were not detected in other tissues, suggesting a brain-specific splicing. We found that the Q/R editing was catalyzed by Adar2 (Adarb1) and required an editing site complementary sequence located in the proximal 5' end of intron 20. Moreover, the Q/R editing was almost exclusively identified in the splicing isoform lacking exon 4, indicating a coupling between the editing and the splicing. Elimination of the Q/R editing in brain-specific Adar2 knockout mice did not affect the splicing efficiency of exon 4. Furthermore, transfection with the splicing isoform containing exon 4 suppressed the Q/R editing in primary cultured cerebellar granule neurons. Thus, our study revealed a coupling between an RNA editing and a distant alternative splicing in the Tmem63b pre-mRNA, in which the splicing plays a dominant role. Finally, physiological analysis showed that the splicing and the editing coordinately regulate Ca2+ permeability and osmosensitivity of channel proteins, which may contribute to their functions in the brain. Full Article
it PDE5 inhibition rescues mitochondrial dysfunction and angiogenic responses induced by Akt3 inhibition by promotion of PRC expression [Bioenergetics] By www.jbc.org Published On :: 2020-12-25T00:06:30-08:00 Akt3 regulates mitochondrial content in endothelial cells through the inhibition of PGC-1α nuclear localization and is also required for angiogenesis. However, whether there is a direct link between mitochondrial function and angiogenesis is unknown. Here we show that Akt3 depletion in primary endothelial cells results in decreased uncoupled oxygen consumption, increased fission, decreased membrane potential, and increased expression of the mitochondria-specific protein chaperones, HSP60 and HSP10, suggesting that Akt3 is required for mitochondrial homeostasis. Direct inhibition of mitochondrial homeostasis by the model oxidant paraquat results in decreased angiogenesis, showing a direct link between angiogenesis and mitochondrial function. Next, in exploring functional links to PGC-1α, the master regulator of mitochondrial biogenesis, we searched for compounds that induce this process. We found that, sildenafil, a phosphodiesterase 5 inhibitor, induced mitochondrial biogenesis as measured by increased uncoupled oxygen consumption, mitochondrial DNA content, and voltage-dependent anion channel protein expression. Sildenafil rescued the effects on mitochondria by Akt3 depletion or pharmacological inhibition and promoted angiogenesis, further supporting that mitochondrial homeostasis is required for angiogenesis. Sildenafil also induces the expression of PGC-1 family member PRC and can compensate for PGC-1α activity during mitochondrial stress by an Akt3-independent mechanism. The induction of PRC by sildenafil depends upon cAMP and the transcription factor CREB. Thus, PRC can functionally substitute during Akt3 depletion for absent PGC-1α activity to restore mitochondrial homeostasis and promote angiogenesis. These findings show that mitochondrial homeostasis as controlled by the PGC family of transcriptional activators is required for angiogenic responses. Full Article
it Murine GFP-Mx1 forms nuclear condensates and associates with cytoplasmic intermediate filaments: Novel antiviral activity against VSV [Immunology] By www.jbc.org Published On :: 2020-12-25T00:06:30-08:00 Type I and III interferons induce expression of the “myxovirus resistance proteins” MxA in human cells and its ortholog Mx1 in murine cells. Human MxA forms cytoplasmic structures, whereas murine Mx1 forms nuclear bodies. Whereas both HuMxA and MuMx1 are antiviral toward influenza A virus (FLUAV) (an orthomyxovirus), only HuMxA is considered antiviral toward vesicular stomatitis virus (VSV) (a rhabdovirus). We previously reported that the cytoplasmic human GFP-MxA structures were phase-separated membraneless organelles (“biomolecular condensates”). In the present study, we investigated whether nuclear murine Mx1 structures might also represent phase-separated biomolecular condensates. The transient expression of murine GFP-Mx1 in human Huh7 hepatoma, human Mich-2H6 melanoma, and murine NIH 3T3 cells led to the appearance of Mx1 nuclear bodies. These GFP-MuMx1 nuclear bodies were rapidly disassembled by exposing cells to 1,6-hexanediol (5%, w/v), or to hypotonic buffer (40–50 mosm), consistent with properties of membraneless phase-separated condensates. Fluorescence recovery after photobleaching (FRAP) assays revealed that the GFP-MuMx1 nuclear bodies upon photobleaching showed a slow partial recovery (mobile fraction: ∼18%) suggestive of a gel-like consistency. Surprisingly, expression of GFP-MuMx1 in Huh7 cells also led to the appearance of GFP-MuMx1 in 20–30% of transfected cells in a novel cytoplasmic giantin-based intermediate filament meshwork and in cytoplasmic bodies. Remarkably, Huh7 cells with cytoplasmic murine GFP-MuMx1 filaments, but not those with only nuclear bodies, showed antiviral activity toward VSV. Thus, GFP-MuMx1 nuclear bodies comprised phase-separated condensates. Unexpectedly, GFP-MuMx1 in Huh7 cells also associated with cytoplasmic giantin-based intermediate filaments, and such cells showed antiviral activity toward VSV. Full Article
it HIV-1 Gag release from yeast reveals ESCRT interaction with the Gag N-terminal protein region [Molecular Bases of Disease] By www.jbc.org Published On :: 2020-12-25T00:06:30-08:00 The HIV-1 protein Gag assembles at the plasma membrane and drives virion budding, assisted by the cellular endosomal complex required for transport (ESCRT) proteins. Two ESCRT proteins, TSG101 and ALIX, bind to the Gag C-terminal p6 peptide. TSG101 binding is important for efficient HIV-1 release, but how ESCRTs contribute to the budding process and how their activity is coordinated with Gag assembly is poorly understood. Yeast, allowing genetic manipulation that is not easily available in human cells, has been used to characterize the cellular ESCRT function. Previous work reported Gag budding from yeast spheroplasts, but Gag release was ESCRT-independent. We developed a yeast model for ESCRT-dependent Gag release. We combined yeast genetics and Gag mutational analysis with Gag-ESCRT binding studies and the characterization of Gag-plasma membrane binding and Gag release. With our system, we identified a previously unknown interaction between ESCRT proteins and the Gag N-terminal protein region. Mutations in the Gag-plasma membrane–binding matrix domain that reduced Gag-ESCRT binding increased Gag-plasma membrane binding and Gag release. ESCRT knockout mutants showed that the release enhancement was an ESCRT-dependent effect. Similarly, matrix mutation enhanced Gag release from human HEK293 cells. Release enhancement partly depended on ALIX binding to p6, although binding site mutation did not impair WT Gag release. Accordingly, the relative affinity for matrix compared with p6 in GST-pulldown experiments was higher for ALIX than for TSG101. We suggest that a transient matrix-ESCRT interaction is replaced when Gag binds to the plasma membrane. This step may activate ESCRT proteins and thereby coordinate ESCRT function with virion assembly. Full Article
it Exploitation of dihydroorotate dehydrogenase (DHODH) and p53 activation as therapeutic targets: A case study in polypharmacology [Computational Biology] By www.jbc.org Published On :: 2020-12-25T00:06:30-08:00 The tenovins are a frequently studied class of compounds capable of inhibiting sirtuin activity, which is thought to result in increased acetylation and protection of the tumor suppressor p53 from degradation. However, as we and other laboratories have shown previously, certain tenovins are also capable of inhibiting autophagic flux, demonstrating the ability of these compounds to engage with more than one target. In this study, we present two additional mechanisms by which tenovins are able to activate p53 and kill tumor cells in culture. These mechanisms are the inhibition of a key enzyme of the de novo pyrimidine synthesis pathway, dihydroorotate dehydrogenase (DHODH), and the blockage of uridine transport into cells. These findings hold a 3-fold significance: first, we demonstrate that tenovins, and perhaps other compounds that activate p53, may activate p53 by more than one mechanism; second, that work previously conducted with certain tenovins as SirT1 inhibitors should additionally be viewed through the lens of DHODH inhibition as this is a major contributor to the mechanism of action of the most widely used tenovins; and finally, that small changes in the structure of a small molecule can lead to a dramatic change in the target profile of the molecule even when the phenotypic readout remains static. Full Article
it A kinetic dissection of the fast and superprocessive kinesin-3 KIF1A reveals a predominant one-head-bound state during its chemomechanical cycle [Molecular Biophysics] By www.jbc.org Published On :: 2020-12-25T00:06:30-08:00 The kinesin-3 family contains the fastest and most processive motors of the three neuronal transport kinesin families, yet the sequence of states and rates of kinetic transitions that comprise the chemomechanical cycle and give rise to their unique properties are poorly understood. We used stopped-flow fluorescence spectroscopy and single-molecule motility assays to delineate the chemomechanical cycle of the kinesin-3, KIF1A. Our bacterially expressed KIF1A construct, dimerized via a kinesin-1 coiled-coil, exhibits fast velocity and superprocessivity behavior similar to WT KIF1A. We established that the KIF1A forward step is triggered by hydrolysis of ATP and not by ATP binding, meaning that KIF1A follows the same chemomechanical cycle as established for kinesin-1 and -2. The ATP-triggered half-site release rate of KIF1A was similar to the stepping rate, indicating that during stepping, rear-head detachment is an order of magnitude faster than in kinesin-1 and kinesin-2. Thus, KIF1A spends the majority of its hydrolysis cycle in a one-head-bound state. Both the ADP off-rate and the ATP on-rate at physiological ATP concentration were fast, eliminating these steps as possible rate-limiting transitions. Based on the measured run length and the relatively slow off-rate in ADP, we conclude that attachment of the tethered head is the rate-limiting transition in the KIF1A stepping cycle. Thus, KIF1A's activity can be explained by a fast rear-head detachment rate, a rate-limiting step of tethered-head attachment that follows ATP hydrolysis, and a relatively strong electrostatic interaction with the microtubule in the weakly bound post-hydrolysis state. Full Article
it Palmitoylation of acetylated tubulin and association with ceramide-rich platforms is critical for ciliogenesis By www.jlr.org Published On :: 2020-12-30 Priyanka TripathiDec 30, 2020; 0:jlr.RA120001190v1-jlr.RA120001190Research Articles Full Article
it High resolution structure of human apolipoprotein (a) kringle IV type 2: beyond the lysine binding site By www.jlr.org Published On :: 2020-12-01 Alice SantonastasoDec 1, 2020; 61:1687-1696Research Articles Full Article
it Nuclear translocation ability of Lipin differentially affects gene expression and survival in fed and fasting Drosophila By www.jlr.org Published On :: 2020-12-01 Stephanie E. HoodDec 1, 2020; 61:1720-1732Research Articles Full Article
it Stimulation of ABCB4/MDR3 ATPase activity requires an intact phosphatidylcholine lipid By www.jlr.org Published On :: 2020-12-01 Martin PrescherDec 1, 2020; 61:1605-1616Research Articles Full Article
it Progression of chronic kidney disease in familial LCAT deficiency: a follow-up of the Italian cohort By www.jlr.org Published On :: 2020-12-01 Chiara PavanelloDec 1, 2020; 61:1784-1788Patient-Oriented and Epidemiological Research Full Article
it Bioavailability and spatial distribution of fatty acids in the rat retina after dietary omega-3 supplementation By www.jlr.org Published On :: 2020-12-01 Elisa VidalDec 1, 2020; 61:1733-1746Research Articles Full Article
it Gene Networks and Pathways for Plasma Lipid Traits via Multi-tissue Multi-omics Systems Analysis By www.jlr.org Published On :: 2020-12-23 Montgomery BlencoweDec 23, 2020; 0:jlr.RA120000713v1-jlr.RA120000713Research Articles Full Article
it Insulin resistance dysregulates CYP7B1 leading to oxysterol accumulation: a pathway for NAFL to NASH transition By www.jlr.org Published On :: 2020-12-01 Genta KakiyamaDec 1, 2020; 61:1629-1644Research Articles Full Article
it The anti-tubercular activity of simvastatin is mediated by cholesterol-driven autophagy via the AMPK-mTORC1-TFEB axis By www.jlr.org Published On :: 2020-12-01 Natalie BruinersDec 1, 2020; 61:1617-1628Research Articles Full Article
it Identification of unusual phospholipids from bovine heart mitochondria by HPLC-MS/MS By www.jlr.org Published On :: 2020-12-01 Junhwan KimDec 1, 2020; 61:1707-1719Research Articles Full Article
it Human CETP lacks lipopolysaccharide transfer activity, but worsens inflammation and sepsis outcomes in mice By www.jlr.org Published On :: 2020-12-09 Aloïs DusuelDec 9, 2020; 0:jlr.RA120000704v1-jlr.RA120000704Research Articles Full Article
it SCD1 promotes lipid mobilization in subcutaneous white adipose tissue By www.jlr.org Published On :: 2020-12-01 Ying ZouDec 1, 2020; 61:1589-1604Research Articles Full Article
it Structure dynamics of ApoA-I amyloidogenic variants in small HDL increase their ability to mediate cholesterol efflux By www.jlr.org Published On :: 2020-11-17 Oktawia NilssonNov 17, 2020; 0:jlr.RA120000920v1-jlr.RA120000920Research Articles Full Article
it Apolipoprotein C3 and apolipoprotein B colocalize in proximity to macrophages in atherosclerotic lesions in diabetes By www.jlr.org Published On :: 2020-12-08 Jenny E. KanterDec 8, 2020; 0:jlr.ILR120001217v1-jlr.ILR120001217Images in Lipid Research Full Article
it Distinct patterns of apolipoprotein C-I, C-II and C-III isoforms are associated with markers of Alzheimers disease By www.jlr.org Published On :: 2020-12-11 Yueming HuDec 11, 2020; 0:jlr.RA120000919v1-jlr.RA120000919Research Articles Full Article
it Generation and validation of a conditional knockout mouse model for the study of the Smith-Lemli-Opitz Syndrome By www.jlr.org Published On :: 2020-11-17 Babunageswararao KanuriNov 17, 2020; 0:jlr.RA120001101v1-jlr.RA120001101Research Articles Full Article
it Adiponectin forms a complex with atherogenic LDL and inhibits its downstream effects By www.jlr.org Published On :: 2020-11-03 Akemi KakinoNov 3, 2020; 0:jlr.RA120000767v1-jlr.RA120000767Research Articles Full Article
it Mass spectrometry characterization of light chain fragmentation sites in cardiac AL amyloidosis: insights into the timing of proteolysis [Genomics and Proteomics] By www.jbc.org Published On :: 2020-12-04T00:06:05-08:00 Amyloid fibrils are polymeric structures originating from aggregation of misfolded proteins. In vivo, proteolysis may modulate amyloidogenesis and fibril stability. In light chain (AL) amyloidosis, fragmented light chains (LCs) are abundant components of amyloid deposits; however, site and timing of proteolysis are debated. Identification of the N and C termini of LC fragments is instrumental to understanding involved processes and enzymes. We investigated the N and C terminome of the LC proteoforms in fibrils extracted from the hearts of two AL cardiomyopathy patients, using a proteomic approach based on derivatization of N- and C-terminal residues, followed by mapping of fragmentation sites on the structures of native and fibrillar relevant LCs. We provide the first high-specificity map of proteolytic cleavages in natural AL amyloid. Proteolysis occurs both on the LC variable and constant domains, generating a complex fragmentation pattern. The structural analysis indicates extensive remodeling by multiple proteases, largely taking place on poorly folded regions of the fibril surfaces. This study adds novel important knowledge on amyloid LC processing: although our data do not exclude that proteolysis of native LC dimers may destabilize their structure and favor fibril formation, the data show that LC deposition largely precedes the proteolytic events documentable in mature AL fibrils. Full Article
it Problem Notes for SAS®9 - 66537: SAS Customer Intelligence Studio becomes non-responsive when you delete a calculated variable from the Edit Value dialog box By Published On :: Tue, 1 Sep 2020 14:25:38 EST In SAS Customer Intelligence Studio, you might notice that the user interface becomes unresponsive, as shown below: imgalt="SAS Customer Intelligence Studio UI becomes unresponsive" src="{fusion_66537 Full Article CAMPAIGNSDO+SAS+Customer+Intelligence+St
it Problem Notes for SAS®9 - 66539: A new calculated variable that you create in the Edit Value dialog box is not available for selection in SAS Customer Intelligence Studio By Published On :: Tue, 1 Sep 2020 13:44:23 EST In SAS Customer Intelligence Studio, you can choose to create a new calculated variable in the Edit Value dialog box when you populate a treatment custom detail. Following creation of the new calculated Full Article CAMPAIGNSDO+SAS+Customer+Intelligence+St
it Problem Notes for SAS®9 - 66542: The initial loading of a rule set and a rule flow takes significantly longer in SAS Business Rules Manager 3.3 compared with release 3.2 By Published On :: Mon, 31 Aug 2020 16:35:05 EST In SAS Business Rules Manager 3.3, the initial loading of a rule set and a rule flow takes significantly longer than it does in release 3.2. When this problem happens, long time gaps are evident in the local Full Article BRLSTBNDL+SAS+Business+Rules+Manager
it Problem Notes for SAS®9 - 66487: Authentication to the CAS server fails with the error "Access denied..." when initiated on a SAS/CONNECT server in a Microsoft Windows environment By Published On :: Mon, 31 Aug 2020 10:33:55 EST You might see the following error messages: "ERROR: Connection failed. Server returned: SAS Logon Manager authentication failed: Access denied." and "ERROR: Unable to connect to Cloud Analytic Services host-name on port 5570. Veri Full Article CONNECT+SAS/CONNECT
it Problem Notes for SAS®9 - 55516: Opening the Edit Action Columns dialog box requires that you wait up to a minute to display a window By Published On :: Fri, 28 Aug 2020 11:23:00 EST Editing and/or saving an action column can take up to a minute to display a window. There are no workarounds identified at this time. Full Article SCDOFR+SAS+Visual+Scenario+Designer
it Problem Notes for SAS®9 - 58465: SAS Life Science Analytics Framework 4.6 - Group membership removal fails with an exception for Process Flows that exist in the Recycle Bin By Published On :: Wed, 26 Aug 2020 16:27:10 EST In SAS Life Science Analytics Framework 4.6, group membership removal fails with an exception if a user is set as assignee, a candidate, or a notification recipient in a user task for a Process Flow . The Process Full Article LSAFOFR+SAS+Life+Science+Analytics+Frame
it Problem Notes for SAS®9 - 33449: An error might occur when you use SAS 9 BULKLOAD= and BULKEXTRACT= options to load data to or extract data from the HP Neoview database on the HP Itanium platform By Published On :: Wed, 26 Aug 2020 16:21:08 EST An error might occur when you use the SAS 9 BULKLOAD= and BULKEXTRACT= options load data to or extract data from HP Neoview on the HP Itanium platform. The problem occurs because Hewlett-Packard changed the name of one of Full Article NEOVIEW+SAS/ACCESS+Interface+to+HP+Neovi
it Problem Notes for SAS®9 - 48028: Custom Time Frame-based data versions do not aggregate correctly when referenced in worksheets with standard hierarchy levels By Published On :: Wed, 26 Aug 2020 16:17:42 EST In SAS Merchandise Financial Planning, custom time frame-based data versions do not aggregate correctly when referenced in worksheets with standard hierarchy levels. The data does not aggregate correctly from l Full Article MMFINANCPLN+SAS+Merchandise+Financial+Pl
it Problem Notes for SAS®9 - 46544: Store layout view has some areas displayed with black fill rather than gray in SAS® Retail Space Management By Published On :: Wed, 26 Aug 2020 16:14:45 EST In SAS Retail Space Management, it should be possible to click on any location object, then Show Properties, and change the location fill color. This can be done on the gray-filled objects. However, w Full Article RTLSPCMGT+SAS+Retail+Space+Management
it Problem Notes for SAS®9 - 61815: SAS Episode Analytics 3.1 - Audit table is required in order to capture user interactions with the user interface By Published On :: Wed, 26 Aug 2020 16:09:53 EST SAS Episode Analytics 3.1 requires the ability to capture user interactions with the user interface for auditing purposes. To support the required functionality a new table has been add Full Article AVAECROFR+SAS+Episode+Analytics