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P-type ATPases in Health and Disease

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889457113 Year: Pages: 256 DOI: 10.3389/978-2-88945-711-3 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Physiology
Added to DOAB on : 2019-01-23 14:53:43
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P-type ATPases are a large group of evolutionary related ion and lipid pumps that have in common that they catalyze a transient phosphorylated intermediate at a key conserved aspartate residue within the pump in order to function. While all the P-type ATPases perform active transport across cellular membranes, they have different transport specificities and serve diverse physiological functions. The ion pumps of the P-type ATPase family create electrochemical gradients that are essential for transepithelial transport, nutrient uptake and membrane potential. They mediate cellular signaling and provide the ligands for metalloenzymes. Phospholipid flippases, also members of the P-type ATPase superfamily, regulate the asymmetric lipid distribution across the lipid bilayer and are critical for the biogenesis of cell membranes. Since all of these ATPases serve fundamental cellular functions, malfunctioning is associated with various pathophysiological processes and dysfunctions of P-type ATPases are known to contribute to cardiovascular, neurological, renal and metabolic diseases. However, with the ever growing knowledge about the diseases associated with the malfunction of P-type ATPases, they are also promising targets for future drug development. In eukaryotes the most prominent examples of P-type ATPases are the Na+,K+-ATPase (sodium pump), the H+-ATPase (proton pump), the H+,K+-ATPase (proton-potassium pump) and the Ca2+-ATPases (calcium pumps). Mutations in the alpha2 and alpha3 subunit of Na,K-ATPase have been associated with neurological diseases, including rapid-onset dystonia-parkinsonism, familial hemiplegic migraine and alternating hemiplegia of childhood. Dysregulation and loss of expression of Na,K-ATPase and plasma membrane Ca-ATPases may be involved in cancer progression. Malfunctioning of the Ca-ATPases is also thought to contribute to hypertension and neurodegenerative diseases and mutations can cause cardiac dysfunction, deafness, hypertension and cerebellar ataxia. Mutations in the SERCA calcium pumps can cause heart failure, Brody myopathy and Darier disease and mutations in the Cu-ATPase genes cause Menkes and Wilson disease. Deficiencies in phospholipid flippases have been linked to progressive familial intrahepatic cholestasis, obesity, diabetes, hearing loss and neurological diseases.

Molecular Organization of Membranes: Where Biology Meets Biophysics

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454099 Year: Pages: 150 DOI: 10.3389/978-2-88945-409-9 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Biology
Added to DOAB on : 2018-11-16 17:17:57
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Biological membranes protect cells and organelles from the surrounding environment, but serve also as organising platforms for physiological processes such as cell signalling. The hydrophobic core of membranes is composed of lipids and proteins influencing each other. Local membrane composition and properties define its molecular organisation and, in this way, regulate the function of all associated molecules. Therefore, studying interactions of components, biophysical properties and overall membrane dynamics provides essential information on its function in the context of cell activities. Such knowledge can contribute to biomedical fields such as pharmacology, immunology, neurobiology and many others. The goal of the Research Topic entitled ‘Molecular organisation of membranes: where biology meets biophysics’ was to provide a comprehensive platform for publishing articles, reviews and opinions focused on membrane organisation and the forces behind its heterogeneous and dynamic structure. We collected 11 works which cover topics as diverse as general membrane organisation models, membrane trafficking and signalling regulation, biogenesis of caveolae, protein-lipid interactions and the importance of membrane-associated tetraspanins networks. The prevalent theme was the existence of membrane nanodomains. To this point, new emerging technologies are presented which own the power to bring a novel insight on how membrane nanodomains are formed and maintained and what is their function. We believe that the collection of works in this Research Topic brings forward some important questions which will stimulate further research in this difficult but exciting field.

Specialised membrane domains of plasmodesmata plant intercellular nanopores

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193684 Year: Pages: 172 DOI: 10.3389/978-2-88919-368-4 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2015-11-19 16:29:12
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Plasmodesmata (PD) are plant-specific intercellular nanopores defined by specialised domains of the plasma membrane (PM) and the endoplasmic reticulum (ER), both of which contain unique proteins, and probably different lipid compositions than the surrounding bulk membranes. The PD membranes form concentric tubules with a minimal outer diameter of only 50 nm, and the central ER strand constricted to ~10-15 nm, representing one of the narrowest stable membrane tubules in nature. This unique membrane architecture poses many biophysical, structural and functional questions. PM continuity across PD raises the question as to how a locally confined membrane site is established and maintained at PD. There is increasing evidence that the PM within PD may be enriched in membrane ‘rafts’ or TET web domains. Lipid rafts often function as signalling platforms, in line with the emerging view of PD as central players in plant defense responses. Lipid-lipid immiscibility could also provide a mechanism for membrane sub- compartmentalisation at PD. Intricate connections of the PM to the wall and the underlying cytoskeleton and ER may anchor the specialised domains locally. The ER within PD is even more strongly modified. Its extreme curvature suggests that it is stabilised by densely packed proteins, potentially members of the reticulon family that tubulate the cortical ER. The diameter of the constricted ER within PD is similar to membrane stalks in dynamin-mediated membrane fission during endocytosis and may need to be stabilised against spontaneous rupture. The function of this extreme membrane constriction, and the reasons why the ER is connected between plant cells remain unknown. Whilst the technically challenging search for the protein components of PD is ongoing, there has been significant recent progress in research on biological membranes that could benefit our understanding of PD function. With this Research Topic, we therefore aim to bring together researchers in the PD field and those in related areas, such as membrane biophysics, membrane composition and fluidity, protein-lipid interactions, lateral membrane heterogeneity, lipid rafts, membrane curvature, and membrane fusion/fission.

A dynamic interplay between membranes and the cytoskeleton critical for cell development and signaling

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889193233 Year: Pages: 80 DOI: 10.3389/978-2-88919-323-3 Language: English
Publisher: Frontiers Media SA
Subject: Botany --- Science (General)
Added to DOAB on : 2016-02-05 17:24:33
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Various cellular processes underlying plant development and response to environmental cues rely on a dynamic interplay between membranes and the cytoskeleton, e.g. vesicle and organelle trafficking, endocytosis, exocytosis, and signal transduction. In recent years, significant progress in the understanding of such interplay has been achieved and several critical links between membranes and the cytoskeleton have been characterized. As an example, recent work has clarified how auxin promotes the reorganization of cortical actin filaments by the activation of Rho GTPase pathways, and how such reorganization in turn locally modifies endocytosis and/or exocytosis and directs asymmetric distribution of PIN family of auxin transporters. Another recent achievement is the characterization of the Rho- and microtubule-driven mechanism by which the cell wall architecture is established. In particular, the elegant work by Oda and Fukuda (Science 337 p.1333, 2012) provides evidence that secondary wall patterning in xylem vessel primarily relies on two processes: a local activation of the plant Rho GTPase ROP11 and a mutual, MIDD1-mediated, inhibitory interaction between active ROP domains and cortical microtubules. Additional examples include recent genetic evidence that microtubule and actin filament interacting/regulatory proteins, such as MAP65-1 and capping protein, function as transducers of membrane lipid signaling into changes in cytoskeleton dynamics and organization. This Research Topic aims at collecting a comprehensive set of articles dealing with cellular processes involving membrane-cytoskeleton interactions. Its scope extends beyond the specific fields defined by the above examples and includes intracellular trafficking, host-pathogen interactions, response to biotic and abiotic stresses and hormonal regulation of growth. We hope that this Research Topic will also highlight critical questions that need to be addressed in the future. We welcomed Original Research Articles, Technical/Methodological Advances (e.g. analysis of cytoskeleton dynamics close to membranes), Reviews and Mini Reviews that can expand our understanding of how and why membranes and the cytoskeleton interact.

Role of lipids in virus assembly

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889195824 Year: Pages: 91 DOI: 10.3389/978-2-88919-582-4 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Microbiology --- Botany
Added to DOAB on : 2016-03-10 08:14:32
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RNA enveloped viruses comprise several families belonging to plus and minus strand RNA viruses, such as retroviruses, flavoviruses and orthomyxoviruses. Viruses utilize cellular lipids during critical steps of replication like entry, assembly and egress. Growing evidence indicate important roles for lipids and lipid nanodomains in virus assembly. This special topic covers key aspects of virus-membrane interactions during assembly and egress, especially those of retroviruses and Ebola virus (EBOV). Virus assembly and release involve specific and nonspecific interactions between viral proteins and membrane compartments. Retroviral Gag proteins assemble predominantly on the PM. Despite the great progress in identifying the factors that modulate retroviral Gag assembly on the PM, there are still gaps in our understanding of precise mechanisms of Gag-membrane interactions. Studies over the last two decades have focused on the mechanisms by which other retroviral Gag proteins interact with membranes during assembly. These include human immunodeficiency virus (HIV), Rous sarcoma virus (RSV), equine infectious anemia virus (EIAV), Mason-Pfizer monkey virus (M-PMV), murine leukemia virus (MLV), and human T-lymphotropic virus type (HTLV-1). Additionally, assembly of filoviruses such as EBOV also occurs on the inner leaflet of the PM. The articles published under this special topic highlight the latest understanding of the role of membrane lipids during virus assembly, egress and release.

Keywords

retroviruses --- HIV 1 --- Gag --- Matrix --- membrane --- NMR --- Ebola --- VP40

Transport of Fluids in Nanoporous Materials

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ISBN: 9783038975298 / 9783038975304 Year: Pages: 260 DOI: 10.3390/books978-3-03897-530-4 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Chemistry (General) --- General and Civil Engineering --- Materials --- Chemical Engineering
Added to DOAB on : 2019-01-25 10:53:11
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Fluid transport in narrow pores is central to the design and optimization of nanoporous materials in industrial applications, such as catalysis, nanofluids, electrochemical batteries, and membrane separation. However, due to the strong potential field in nanopores, conventional models and methods have become inadequate for predicting the transport behavior of molecules confined in the pore space. In addition, the inherent complexity of the pore structure in nanomaterials requires consideration of local or nanoscale transport at the single pore level, and averaging over the macroscale, which further impedes the application and validation of the formulated mechanical models. To solve the problem of fluid transport in narrow nanopores beyond Knudsen limits, experimental characterizations should be combined to molecular simulations in order to probe the fluid movement under realistic conditions. This book provides comprehensive perspectives on the current research in the investigation of fluid transport processes in nanomaterials. The articles from leading scholars in this field are conveniently arranged according to three categories based on the approaches used in the papers: modeling and simulation, nanomaterial manipulation and characterization, and practical application. The 14 contributions not only demonstrate the importance of fluid behavior in different applications but also address the main theories and simulations to model the fluid transport behavior in nanoporous materials. This collection shows that “fluid transport in nanomaterials” remains a versatile and vibrant topic in terms of both theories and applications.

Pd-based Membranes. Overview and Perspectives

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ISBN: 9783038977025 Year: Pages: 190 DOI: 10.3390/books978-3-03897-703-2 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Chemical Engineering --- Technology (General)
Added to DOAB on : 2019-04-05 10:34:31
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Palladium (Pd)-based membranes have received a great deal of attention from both academia and industry thanks to their ability to selectively separate hydrogen from gas streams. The integration of such membranes with appropriate catalysts in membrane reactors allows for hydrogen production with CO2 capture that can be applied in smaller bioenergy or combined heat and power (CHP) plants, as well as in large-scale power plants. Pd-based membranes are therefore regarded as a Key Enabling Technology (KET) to facilitate the transition towards a knowledge-based, low-carbon, and resource-efficient economy. This Special Issue of the journal Membranes on “Pd-based Membranes: Overview and Perspectives” contains nine peer-reviewed articles. Topics include manufacturing techniques, understanding of material phenomena, module and reactor design, novel applications, and demonstration efforts and industrial exploitation.

Novel Membrane Technologies for Traditional Industrial Processes

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ISBN: 9783038977902 / 9783038977919 Year: Pages: 196 DOI: 10.3390/books978-3-03897-791-9 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Physics (General)
Added to DOAB on : 2019-08-28 11:21:27
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Through reading this book, you will obtain information on: (1) the main problems in air separation and natural gas treatment by membrane separation and how to solve them; (2) processes involving membranes and new membrane materials for the more economical utilization of bio-resources; (3) energy selection and membrane development for more expedient and stable harnessing of the natural osmosis phenomenon; (4) many excellent contributions about catalytic membrane bioreactors; (5) how to fine-tune the arrangement of aquaporins (i.e., proteins identified in biological cells) to achieve superior water treatment efficiency.

Cellular Entry of Binary and Pore-Forming Bacterial Toxins

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ISBN: 9783038427049 9783038427032 Year: Pages: 128 DOI: 10.3390/books978-3-03842-703-2 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Biology
Added to DOAB on : 2018-02-08 13:26:54
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Bridging cellular membranes is a key step in the pathogenic action of both binary and pore-forming bacterial toxins. The former use their translocation domains, containing various structural motifs, to ensure efficient delivery of the toxic component into the host cell, while the latter act on the cellular membrane itself. In either case, the integrity of the membrane is compromised via targeted protein–lipid and protein–protein interactions triggered by specific signals, such as proteolytic cleavage or endosomal acidification.This Special Issue presents recent advances in characterizing functional, structural and thermodynamic aspects of the conformational switching and membrane interactions involved in the cellular entry of bacterial protein toxins. Deciphering the physicochemical principles underlying these processes is also a prerequisite for the use of protein engineering to develop toxin-based molecular vehicles capable of targeted delivery of therapeutic agents to tumors and other diseased tissues.

Membrane and Membrane Reactors Operations in Chemical Engineering

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ISBN: 9783039210220 / 9783039210237 Year: Pages: 154 DOI: 10.3390/books978-3-03921-023-7 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering --- Environmental Engineering
Added to DOAB on : 2019-06-26 10:09:00
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This Special Issue is aimed at highlighting the potentialities of membrane and membrane reactor operations in various sectors of chemical engineering, based on application of the process intensification strategy. In all of the contributions, the principles of process intensification were pursued during the adoption of membrane technology, demonstrating how it may lead to the development of redesigned processes that are more compact and efficient while also being more environmental friendly, energy saving, and amenable to integration with other green processes. This Special Issue comprises a number of experimental and theoretical studies dealing with the application of membrane and membrane reactor technology in various scientific fields of chemical engineering, such as membrane distillation for wastewater treatment, hydrogen production from reforming reactions via inorganic membrane and membrane photoassisted reactors, membrane desalination, gas/liquid phase membrane separation of CO2, and membrane filtration for the recovery of antioxidants from agricultural byproducts, contributing to valorization of the potentialities of membrane operations.

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