scholarly journals Nuclear and cytoplasmic huntingtin inclusions exhibit distinct biochemical composition, interactome and ultrastructural properties

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nathan Riguet ◽  
Anne-Laure Mahul-Mellier ◽  
Niran Maharjan ◽  
Johannes Burtscher ◽  
Marie Croisier ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Protein Quality ◽  
Protein Composition ◽  
Cytoskeletal Proteins ◽  
Primary Neurons ◽  
Inclusion Formation ◽  
Complex Processes ◽  
Mechanisms Of Formation ◽  
Biochemical Compositions ◽  
Insight Into

AbstractDespite the strong evidence linking the aggregation of the Huntingtin protein (Htt) to the pathogenesis of Huntington’s disease (HD), the mechanisms underlying Htt aggregation and neurodegeneration remain poorly understood. Herein, we investigated the ultrastructural properties and protein composition of Htt cytoplasmic and nuclear inclusions in mammalian cells and primary neurons overexpressing mutant exon1 of the Htt protein. Our findings provide unique insight into the ultrastructural properties of cytoplasmic and nuclear Htt inclusions and their mechanisms of formation. We show that Htt inclusion formation and maturation are complex processes that, although initially driven by polyQ-dependent Htt aggregation, also involve the polyQ and PRD domain-dependent sequestration of lipids and cytoplasmic and cytoskeletal proteins related to HD dysregulated pathways; the recruitment and accumulation of remodeled or dysfunctional membranous organelles, and the impairment of the protein quality control and degradation machinery. We also show that nuclear and cytoplasmic Htt inclusions exhibit distinct biochemical compositions and ultrastructural properties, suggesting different mechanisms of aggregation and toxicity.

scholarly journals Disentangling the sequence, cellular and ultrastructural determinants of Huntingtin nuclear and cytoplasmic inclusion formation

2020 ◽  
Author(s):  
Nathan Riguet ◽  
Anne-Laure Mahul-Mellier ◽  
Niran Maharjan ◽  
Johannes Burtscher ◽  
Alice Patin ◽  
...  
Keyword(s):  
Protein Quality ◽  
Cytoplasmic Inclusion ◽  
Protein Composition ◽  
Cytoskeletal Proteins ◽  
Formation Mechanisms ◽  
Cytoplasmic Inclusions ◽  
Inclusion Formation ◽  
Complex Processes ◽  
Mechanisms Of Formation ◽  
Insight Into

AbstractDespite the strong evidence linking the aggregation of the Huntingtin protein (Htt) to the pathogenesis of Huntington’s disease (HD), the mechanisms underlying Htt aggregation and neurodegeneration remain poorly understood. Herein, we investigated the ultrastructural properties and protein composition of Htt inclusions in cells overexpressing mutant exon1 of the Htt protein. Our findings provide novel insight into the ultrastructural properties of cytoplasmic and nuclear Htt inclusions and their mechanisms of formation. We show that Htt inclusion formation and maturation are complex processes that, although initially driven by polyQ-dependent Htt aggregation, also involve 1) polyQ and PRD domain-dependent sequestration of lipids and cytoplasmic and cytoskeletal proteins related to HD dysregulated pathways; 2) recruitment and accumulation of remodeled or dysfunctional membranous organelles; and 3) impairement of the protein quality control and degradation machineries. Interestingly, nuclear and cytoplasmic Htt inclusions exhibited distinct biochemical composition and ultrastructural properties, suggesting different formation mechanisms and toxicity.Graphical AbstractSchematic depictions and original electron micrographs of cytoplasmic inclusions formed by native (tag-free) mutant Huntington exon1 proteins (Httex1 72Q, left) and the corresponding GFP fusion protein (Httex1 72Q-GFP).

scholarly journals Racemization-free synthesis of Nα-2-thiophenoyl-phenylalanine-2-morpholinoanilide enantiomers and their antimycobacterial activity

Amino Acids ◽  
2021 ◽  
Author(s):  
Lea Mann ◽  
Markus Lang ◽  
Philipp Schulze ◽  
Jan Henrik Halz ◽  
René Csuk ◽  
...  
Keyword(s):  
Title Compound ◽  
Mammalian Cells ◽  
Antimycobacterial Activity ◽  
Lead Compound ◽  
Coupling Reagents ◽  
Hydrogen Bonding Interactions ◽  
Amide Coupling ◽  
Subsequent Separation ◽  
Synthetic Routes ◽  
Insight Into

AbstractNα-2-thiophenoyl-d-phenylalanine-2-morpholinoanilide (MMV688845, IUPAC: N-(1-((2-morpholinophenyl)amino)-1-oxo-3-phenylpropan-2-yl)thiophene-2-carboxamide) from the Pathogen Box® library (Medicines for Malaria Ventures, MMV) is a promising lead compound for antimycobacterial drug development. Two straightforward synthetic routes to the title compound starting from phenylalanine or its Boc-protected derivative are reported. Employing Boc-phenylalanine as starting material and the T3P® and PyBOP® amide coupling reagents enables racemization-free synthesis, avoiding the need for subsequent separation of the enantiomers. The crystal structure of the racemic counterpart gives insight into the molecular structure and hydrogen bonding interactions in the solid state. The R-enantiomer of the title compound (derived from d-phenylalanine) exhibits activity against non-pathogenic and pathogenic mycobacterial strains, whereas the S-enantiomer is inactive. Neither of the enantiomers and the racemate of the title compound shows cytotoxicity against various mammalian cells.

Coordination of Complex Product Development Processes

2010 ◽  
Author(s):  
Samuel Suss ◽  
Vincent Thomson
Keyword(s):  
Product Development ◽  
Product Development Process ◽  
Complex Products ◽  
Complex Processes ◽  
The Status ◽  
Development Processes ◽  
Correct Understanding ◽  
Vital Element ◽  
Insight Into ◽  
Product Development Processes

Product development processes of complex products are complex themselves and particularly difficult to plan and manage effectively. Although many organizations manage their product development processes by monitoring the status of documents that are created as deliverables, in fact the progress of the process is in large part based on the actual information flow which is required to develop the product and produce the documents. A vital element in making product development processes work well is the correct understanding of how information flows and how to facilitate its development. In this paper we describe an executable stochastic model of the product development process that incorporates the salient features of the interplay between the information development, exchange and progress of the technical work. Experiments with the model provide insight into the mechanisms that drive these complex processes.

Protein composition of nuclear matrix preparations from HeLa cells: an immunochemical approach

1986 ◽  
Vol 80 (1) ◽  
pp. 103-122
Author(s):  
R. Verheijen ◽  
H. Kuijpers ◽  
P. Vooijs ◽  
W. van Venrooij ◽  
F. Ramaekers
Keyword(s):  
Nuclear Matrix ◽  
Connective Tissue Diseases ◽  
Protein Composition ◽  
Cytoskeletal Proteins ◽  
Two Dimensional ◽  
Two Dimensional Gel Electrophoresis ◽  
Core Proteins ◽  
Nuclear Rna ◽  
Hela S3 ◽  
Protein Components

Procedures for the isolation of HeLa S3 nuclear matrices were re-examined with special emphasis on the use of various nucleases and detergents as well as on the ionic strength of the final salt extraction. The protein composition of the resulting nuclear matrix preparations was analysed by one- and two-dimensional gel electrophoresis and found to be extremely reproducible. By means of co-electrophoresis several typical cytoskeletal proteins (actin, vimentin and cytokeratins) and heterogeneous nuclear RNA (hnRNA)-associated core proteins (hnRNP) were shown to be present in such nuclear matrix preparations. The nature of some other protein components was elucidated using two-dimensional immunoblotting and immunofluorescence. For this purpose mouse monoclonal antibodies to cytoskeletal components (vimentin, cytokeratins), small nuclear RNP (70 X 10(3) Mr protein of U1-RNP), hnRNP (C1/C2) and the pore-complex lamina (lamins A, B and C) were used next to human autoimmune sera obtained from patients with connective tissue diseases and directed against the residual nucleoli and the internal fibrillar mass. These antibodies enabled us to identify a number of proteins present specifically in the nuclear matrix and to show that part of the cytoskeletal proteins are still present in the isolated structures.

scholarly journals The intracellular dynamic of protein palmitoylation

2010 ◽  
Vol 191 (7) ◽  
pp. 1229-1238 ◽  
Author(s):  
Christine Salaun ◽  
Jennifer Greaves ◽  
Luke H. Chamberlain
Keyword(s):  
Posttranslational Modifications ◽  
Posttranslational Modification ◽  
Mammalian Cells ◽  
Protein Functionality ◽  
Peripheral Membrane Proteins ◽  
Protein Palmitoylation ◽  
Thioester Bond ◽  
Intracellular Sorting ◽  
Intracellular Dynamic ◽  
Insight Into

S-palmitoylation describes the reversible attachment of fatty acids (predominantly palmitate) onto cysteine residues via a labile thioester bond. This posttranslational modification impacts protein functionality by regulating membrane interactions, intracellular sorting, stability, and membrane micropatterning. Several recent findings have provided a tantalizing insight into the regulation and spatiotemporal dynamics of protein palmitoylation. In mammalian cells, the Golgi has emerged as a possible super-reaction center for the palmitoylation of peripheral membrane proteins, whereas palmitoylation reactions on post-Golgi compartments contribute to the regulation of specific substrates. In addition to palmitoylating and depalmitoylating enzymes, intracellular palmitoylation dynamics may also be controlled through interplay with distinct posttranslational modifications, such as phosphorylation and nitrosylation.

scholarly journals Intercellular transmission of a bacterial cytotoxic prion-like protein in mammalian cells

2019 ◽  
Author(s):  
Aida Revilla-García ◽  
Cristina Fernández ◽  
María Moreno-del Álamo ◽  
Vivian de los Ríos ◽  
Ina M. Vorberg ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Protein Quality ◽  
Horizontal Cell ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cells ◽  
Neuroblastoma Cell Line ◽  
Human Neuroblastoma ◽  
Intracellular Traffic ◽  
First Time

AbstractRepA is a bacterial protein that builds intracellular amyloid oligomers acting as inhibitory complexes of plasmid DNA replication. When carrying a mutation enhancing its amyloidogenesis (A31V), the N-terminal domain (WH1) generates cytosolic amyloid particles that are inheritable within a bacterial lineage. Such amyloids trigger in bacteria a lethal cascade reminiscent to mitochondria impairment in human cells affected by neurodegeneration. To fulfil all the features of a prion-like protein, horizontal (intercellular) transmissibility remains to be demonstrated for RepA-WH1. Since this is experimentally intractable in bacteria, here we transiently expressed in a murine neuroblastoma cell line the soluble, barely cytotoxic RepA-WH1(WT) and assayed its response to co-incubation with in vitro assembled RepA-WH1(A31V) amyloid fibres. In parallel, cells releasing RepA-WH1(A31V) aggregates were co-cultured with human neuroblastoma cells expressing RepA-WH1(WT). Both the assembled fibres and the extracellular RepA-WH1(A31V) aggregates induce, in the cytosol of recipient cells, the formation of cytotoxic amyloid particles. Mass spectrometry analyses of the proteomes of both types of injured cells point to alterations in mitochondria, protein quality triage, signalling and intracellular traffic.Summary blurbThe horizontal, cell-to-cell spread of a bacterial prion-like protein is shown for the first time in mammalian cells. Amyloid cross-aggregation of distinct variants, and their associated toxicities, follow the same trend found in bacteria, underlining the universality of prion biology.

scholarly journals A systematic characterization of intrinsically formed microglia-like cells during retinal organoid differentiation.

2022 ◽  
Author(s):  
Katarina Bartalska ◽  
Verena Hübschmann ◽  
Medina Korkut-Demirbaş ◽  
Ryan John Abat Cubero ◽  
Alessandro Venturino ◽  
...  
Keyword(s):  
Protein Composition ◽  
Human Microglia ◽  
Development Organization ◽  
Cellular Environment ◽  
Preferential Localization ◽  
Circuit Development ◽  
And Migration ◽  
Induced Pluripotent ◽  
Insight Into

Brain organoids differentiated from human induced pluripotent stem cells provide a unique opportunity to investigate the development, organization and connectivity of neurons in a complex cellular environment. However, organoids usually lack microglia, brain-resident immune cells which are both present in the early human embryonic brain and participate in neuronal circuit development. Here, we find that microglia innately develop in unguided retinal organoid differentiation between week 3 and 4 in 2.5D culture and appear later in floating, non-pigmented, 3D-cystic compartments. We enriched for cystic structures using a low-dosed BMP4 application and performed mass spectrometry, thus defining the protein composition of microglia-containing compartments. We found that cystic compartments expressed both mesenchymal and epithelial markers with microglia enriched in the mesenchymal region. Interestingly, microglia-like cells started to express the border-associated macrophage marker CD163. The preferential localization of human microglia to a mesenchymal compartment provides insight into the behavior and migration of microglia. The model will ultimately allow detailed study of these enigmatic cells and how they enter and distribute within the human brain.

Chemical carcinogens

2019 ◽  
pp. 79-90
Author(s):  
David H. Phillips
Keyword(s):  
Dna Repair ◽  
Cancer Incidence ◽  
Mammalian Cells ◽  
Human Exposure ◽  
Chemical Carcinogens ◽  
Regulatory Processes ◽  
Genotoxic Carcinogens ◽  
The Many ◽  
Transformation Methods ◽  
Insight Into

Large geographical and temporal differences in cancer incidence indicate that the causes of the majority of cases are a consequence of environmental and lifestyle factors. While many of these remain unknown, around half have known causes, and these include chemicals in air, water, and food, as well as products of industrial processes and of combustion. The major classes of chemical carcinogens and how they were discovered are described. A property shared by many of them is that they, or one or more of their metabolites, are electrophiles that can damage DNA in mammalian cells, leading to cellular responses including DNA repair, cytotoxicity, apoptosis, mutagenesis, and malignant transformation. Methods for predicting the carcinogenicity of new chemicals are part of the regulatory processes for safety assessment, and sensitive methods for monitoring human exposure to carcinogens provide insight into the aetiology of cancer. The mutational signatures that genotoxic carcinogens leave in the tumours they induce provide evidence of the chemicals that have caused them, and the approach has promise for shedding light on the many as-yet-unidentified cases of cancer worldwide.

scholarly journals Role for ribosome-associated quality control in sampling proteins for MHC class I-mediated antigen presentation

2020 ◽  
Vol 117 (8) ◽  
pp. 4099-4108 ◽  
Author(s):  
Débora Broch Trentini ◽  
Matteo Pecoraro ◽  
Shivani Tiwary ◽  
Jürgen Cox ◽  
Matthias Mann ◽  
...  
Keyword(s):  
Quality Control ◽  
Antigen Presentation ◽  
Mammalian Cells ◽  
Adaptive Immune System ◽  
Messenger Rnas ◽  
Mhc I ◽  
Adaptive Immune ◽  
Ribosome Stalling ◽  
Endogenous Substrates ◽  
Insight Into

Mammalian cells present a fingerprint of their proteome to the adaptive immune system through the display of endogenous peptides on MHC-I complexes. MHC-I−bound peptides originate from protein degradation by the proteasome, suggesting that stably folded, long-lived proteins could evade monitoring. Here, we investigate the role in antigen presentation of the ribosome-associated quality control (RQC) pathway for the degradation of nascent polypeptides that are encoded by defective messenger RNAs and undergo stalling at the ribosome during translation. We find that degradation of model proteins by RQC results in efficient MHC-I presentation, independent of their intrinsic folding properties. Quantitative profiling of MHC-I peptides in wild-type and RQC-deficient cells by mass spectrometry showed that RQC substantially contributes to the composition of the immunopeptidome. Our results also identify endogenous substrates of the RQC pathway in human cells and provide insight into common principles causing ribosome stalling under physiological conditions.

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