scholarly journals The Role of Cell Membranes in Cell Traffic

2022 ◽  
Vol 1 (6) ◽  
pp. 149-162
Author(s):  
Rara Inggarsih ◽  
Ella Amalia ◽  
Septi Purnamasari
Keyword(s):  
Cell Membrane ◽  
Transport System ◽  
Metabolic Pathways ◽  
Strong Influence ◽  
Cell Membranes ◽  
Cell Compartment ◽  
Cell Transport ◽  
Selective Transport

The cell membrane plays an important role in cell traffic because it functions to secrete various molecules. The selective transport system allows the movement of molecules into or out of the cell compartment. By controlling the movement of substances from one compartment to another, membranes exert a strong influence on metabolic pathways. Cell membranes are composed of proteins and lipids with a very important function in maintaining the rhythm of circulation and cell transport. In addition, the cell membrane also plays a role in maintaining the integrity and relationship, and communication of cells.

scholarly journals Concerted interactions between multiple gp41 trimers and the target cell lipidome may be required for HIV-1 entry

2020 ◽  
Author(s):  
Biswajit Gorai ◽  
Anil Kumar Sahoo ◽  
Anand Srivastava ◽  
Narendra M. Dixit ◽  
Prabal K. Maiti
Keyword(s):  
Cell Membrane ◽  
Host Cell ◽  
Target Cell ◽  
Cell Membranes ◽  
Molecular Level ◽  
Membrane Lipid ◽  
Coarse Grained ◽  
Free Energy Barrier ◽  
Hiv 1

ABSTRACTThe HIV-1 envelope glycoprotein gp41 mediates the fusion between viral and host cell membranes leading to virus entry and target cell infection. Despite years of research, important aspects of this process such as the number of gp41 trimers involved and how they orchestrate the rearrangement of the lipids in the apposed membranes along the fusion pathway remain obscure. To elucidate these molecular underpinnings, we performed coarse-grained molecular dynamics simulations of HIV-1 virions pinned to the CD4 T cell membrane by different numbers of gp41 trimers. We built realistic cell and viral membranes by mimicking their respective lipid compositions. We found that a single gp41 was inadequate for mediating fusion. Lipid mixing between membranes, indicating the onset of fusion, was efficient when 3 or more gp41 trimers pinned the membranes. The gp41 trimers interacted strongly with many different lipids in the host cell membrane, triggering lipid configurational rearrangements, exchange, and mixing. Simpler membranes, comprising fewer lipid types, displayed strong resistance to fusion, revealing the crucial role of the lipidomes in HIV-1 entry. Performing simulations at different temperatures, we estimated the free energy barrier to lipid mixing, and hence membrane stalk formation, with 4 tethering gp41 trimers to be ~6.2 kcal/mol, a >4-fold reduction over estimates without gp41. Together, these findings present molecular-level, quantitative insights into the early stages of gp41-mediated HIV-1 entry. Preventing the requisite gp41 molecules from tethering the membranes or altering membrane lipid compositions may be potential intervention strategies.SIGNIFICANCEInteractions between viral envelope proteins and host cell surface receptors leading to HIV-1 entry are well studied, however the role of membrane lipids remains obscure, although entry hinges on lipid mixing and the fusion of viral and cell membranes. We performed detailed simulations of HIV-1 and target cell membranes tethered by viral gp41 trimeric proteins to elucidate the proteo-lipidic contributions to viral entry. We found that the cooperative effects of multiple gp41 trimers and natural lipidomes of the membranes facilitate membrane fusion. The functional domains of gp41 altered local lipid concentrations, reduced membrane repulsions, and facilitated inter-membrane lipid mixing. These molecular-level insights offer a glimpse of the cryptic mechanisms underlying HIV-1 entry and suggest new interventions to combat HIV-1 infection.

Molecular transport at cell membranes

1965 ◽  
Vol 163 (991) ◽  
pp. 169-196 ◽  
Keyword(s):  
Cell Membrane ◽  
Cell Membranes ◽  
Diffusion Processes ◽  
Molecular Transport ◽  
Transport Processes ◽  
Passive Diffusion ◽  
Cell Compartment ◽  
Normal Diffusion ◽  
A Cell ◽  
And Function

It has become increasingly evident during the last decade that cell membranes are equipped with factors that play specific roles in conveying both inorganic and organic substances from the cell exterior to the cell interior or from one compartment in the cell to another. The normal diffusion processes (often called passive diffusion) occur but these may be slow, the rates depending on the concentrations of the substances involved. Passive diffusion leads only to a concentration within the cell no higher than that outside except under circumstances where binding of the substance, to a cell constituent, takes place in the cell or in a cell compartment. The components in the cell membrane that control the rates of ionic and molecular transport, and which may lead to the attainment of concentrations of ions and molecules in the cell substantially higher than those outside, may play roles as important as those of the enzymes in the control of cell growth, metabolism and function. The process whereby a substance is transferred across the cell membrane in such a manner that it is specifically controlled, that it can lead to accumulation of the substance in the cell against a concentration gradient, and that it is energy assisted, i. e. coupled with metabolic processes, is often referred to as active transport. The specific components located at the cell membrane and involved in the transport processes are usually termed transport carriers.

The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface

1999 ◽  
Vol 39 (7) ◽  
pp. 91-98 ◽  
Author(s):  
Ryan N. Jordan ◽  
Eric P. Nichols ◽  
Alfred B. Cunningham
Keyword(s):  
Mass Transfer ◽  
Cell Membrane ◽  
Substrate Concentration ◽  
Water Interface ◽  
Industrial Systems ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Surfactant Sorption

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.

scholarly journals The Ability of Metabolomics to Discriminate Non-Small-Cell Lung Cancer Subtypes Depends on the Stage of the Disease and the Type of Material Studied

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3314
Author(s):  
Tomasz Kowalczyk ◽  
Joanna Kisluk ◽  
Karolina Pietrowska ◽  
Joanna Godzien ◽  
Miroslaw Kozlowski ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Early Stage ◽  
Chronic Obstructive ◽  
Liquid Chromatography Mass Spectrometry ◽  
Obstructive Pulmonary Disease ◽  
Cell Lung Carcinoma ◽  
Cancer Subtypes ◽  
Inflammatory State ◽  
Nsclc Patients

Identification of the NSCLC subtype at an early stage is still quite sophisticated. Metabolomics analysis of tissue and plasma of NSCLC patients may indicate new, and yet unknown, metabolic pathways active in the NSCLC. Our research characterized the metabolomics profile of tissue and plasma of patients with early and advanced NSCLC stage. Samples were subjected to thorough metabolomics analyses using liquid chromatography-mass spectrometry (LC-MS) technique. Tissue and/or plasma samples from 137 NSCLC patients were analyzed. Based on the early stage tissue analysis, more than 200 metabolites differentiating adenocarcinoma (ADC) and squamous cell lung carcinoma (SCC) subtypes as well as normal tissue, were identified. Most of the identified metabolites were amino acids, fatty acids, carnitines, lysoglycerophospholipids, sphingomyelins, plasmalogens and glycerophospholipids. Moreover, metabolites related to N-acyl ethanolamine (NAE) biosynthesis, namely glycerophospho (N-acyl) ethanolamines (GP-NAE), which discriminated early-stage SCC from ADC, have also been identified. On the other hand, the analysis of plasma of chronic obstructive pulmonary disease (COPD) and NSCLC patients allowed exclusion of the metabolites related to the inflammatory state in lungs and the identification of compounds (lysoglycerophospholipids, glycerophospholipids and sphingomyelins) truly characteristic to cancer. Our results, among already known, showed novel, thus far not described, metabolites discriminating NSCLC subtypes, especially in the early stage of cancer. Moreover, the presented results also indicated the activity of new metabolic pathways in NSCLC. Further investigations on the role of NAE biosynthesis pathways in the early stage of NSCLC may reveal new prognostic and diagnostic targets.

scholarly journals The Role of Cell Metabolism in Innate Immune Memory

2020 ◽  
pp. 1-9
Author(s):  
Anaisa Valido Ferreira ◽  
Jorge Domiguéz-Andrés ◽  
Mihai Gheorghe Netea
Keyword(s):  
Metabolic Pathways ◽  
Tricarboxylic Acid Cycle ◽  
Cell Metabolism ◽  
Innate Immune ◽  
Immune Memory ◽  
Functional Changes ◽  
Trained Immunity ◽  
Health And Disease

Immunological memory is classically attributed to adaptive immune responses, but recent studies have shown that challenged innate immune cells can display long-term functional changes that increase nonspecific responsiveness to subsequent infections. This phenomenon, coined <i>trained immunity</i> or <i>innate immune memory</i>, is based on the epigenetic reprogramming and the rewiring of intracellular metabolic pathways. Here, we review the different metabolic pathways that are modulated in trained immunity. Glycolysis, oxidative phosphorylation, the tricarboxylic acid cycle, amino acid, and lipid metabolism are interplaying pathways that are crucial for the establishment of innate immune memory. Unraveling this metabolic wiring allows for a better understanding of innate immune contribution to health and disease. These insights may open avenues for the development of future therapies that aim to harness or dampen the power of the innate immune response.

scholarly journals Mitochondrial Sirtuins in Reproduction

Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1047
Author(s):  
Giovanna Di Emidio ◽  
Stefano Falone ◽  
Paolo Giovanni Artini ◽  
Fernanda Amicarelli ◽  
Anna Maria D’Alessandro ◽  
...  
Keyword(s):  
Stress Responses ◽  
Metabolic Pathways ◽  
Redox Balance ◽  
Antioxidant Defenses ◽  
Metabolic Abnormalities ◽  
Female Reproduction ◽  
Mitochondrial Dysfunctions ◽  
Early Embryos ◽  
The Relationship

Mitochondria act as hubs of numerous metabolic pathways. Mitochondrial dysfunctions contribute to altering the redox balance and predispose to aging and metabolic alterations. The sirtuin family is composed of seven members and three of them, SIRT3-5, are housed in mitochondria. They catalyze NAD+-dependent deacylation and the ADP-ribosylation of mitochondrial proteins, thereby modulating gene expression and activities of enzymes involved in oxidative metabolism and stress responses. In this context, mitochondrial sirtuins (mtSIRTs) act in synergistic or antagonistic manners to protect from aging and aging-related metabolic abnormalities. In this review, we focus on the role of mtSIRTs in the biological competence of reproductive cells, organs, and embryos. Most studies are focused on SIRT3 in female reproduction, providing evidence that SIRT3 improves the competence of oocytes in humans and animal models. Moreover, SIRT3 protects oocytes, early embryos, and ovaries against stress conditions. The relationship between derangement of SIRT3 signaling and the imbalance of ROS and antioxidant defenses in testes has also been demonstrated. Very little is known about SIRT4 and SIRT5 functions in the reproductive system. The final goal of this work is to understand whether sirtuin-based signaling may be taken into account as potential targets for therapeutic applications in female and male infertility.

scholarly journals The Pleiotropic Function of Human Sirtuins as Modulators of Metabolic Pathways and Viral Infections

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 460
Author(s):  
Mohammed Hamed Alqarni ◽  
Ahmed Ibrahim Foudah ◽  
Magdy Mohamed Muharram ◽  
Nikolaos E. Labrou
Keyword(s):  
Metabolic Pathways ◽  
Histone Deacetylases ◽  
Viral Infections ◽  
Cell Physiology ◽  
Functional Roles ◽  
Regulatory Processes ◽  
Complex Functions ◽  
Natural Polyphenol ◽  
Antiviral Targets

Sirtuins (SIRTs) are nicotinamide adenine dinucleotide-dependent histone deacetylases that incorporate complex functions in the mechanisms of cell physiology. Mammals have seven distinct members of the SIRT family (SIRT1-7), which play an important role in a well-maintained network of metabolic pathways that control and adapt the cell to the environment, energy availability and cellular stress. Until recently, very few studies investigated the role of SIRTs in modulating viral infection and progeny. Recent studies have demonstrated that SIRT1 and SIRT2 are promising antiviral targets because of their specific connection to numerous metabolic and regulatory processes affected during infection. In the present review, we summarize some of the recent progress in SIRTs biochemistry and their emerging function as antiviral targets. We also discuss the potential of natural polyphenol-based SIRT modulators to control their functional roles in several diseases including viral infections.

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