scholarly journals Homeostatic restitution of cell membranes. Nuclear membrane lipid biogenesis and transport of protein from cytosol to intranuclear spaces.

2006 ◽  
pp. 216-226 ◽  
Author(s):  
Amalia Slomiany ◽  
Maria Grabska ◽  
Bronislaw L. Slomiany
Keyword(s):  
Nuclear Membrane ◽  
Cell Membranes ◽  
Membrane Lipid

scholarly journals High light induces species specific changes in the membrane lipid composition of Chlorella

2020 ◽  
Vol 477 (13) ◽  
pp. 2543-2559
Author(s):  
Janka Widzgowski ◽  
Alexander Vogel ◽  
Lena Altrogge ◽  
Julia Pfaff ◽  
Heiko Schoof ◽  
...  
Keyword(s):  
Cell Membranes ◽  
De Novo ◽  
Algal Cell ◽  
Isotopic Labeling ◽  
Biochemical Properties ◽  
Membrane Lipid ◽  
Light Conditions ◽  
Hydrophobic Barrier ◽  
Glycerolipid Composition ◽  
Species Specific

Algae have evolved several mechanisms to adjust to changing environmental conditions. To separate from their surroundings, algal cell membranes form a hydrophobic barrier that is critical for life. Thus, it is important to maintain or adjust the physical and biochemical properties of cell membranes which are exposed to environmental factors. Especially glycerolipids of thylakoid membranes, the site of photosynthesis and photoprotection within chloroplasts, are affected by different light conditions. Since little is known about membrane lipid remodeling upon different light treatments, we examined light induced alterations in the glycerolipid composition of the two Chlorella species, C. vulgaris and C. sorokiniana, which differ strongly in their ability to cope with different light intensities. Lipidomic analysis and isotopic labeling experiments revealed differences in the composition of their galactolipid species, although both species likely utilize galactolipid precursors originated from the endoplasmic reticulum. However, in silico research of de novo sequenced genomes and ortholog mapping of proteins putatively involved in lipid metabolism showed largely conserved lipid biosynthesis pathways suggesting species specific lipid remodeling mechanisms, which possibly have an impact on the response to different light conditions.

scholarly journals Interaction of Local Anesthetics with Biomembranes Consisting of Phospholipids and Cholesterol: Mechanistic and Clinical Implications for Anesthetic and Cardiotoxic Effects

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Hironori Tsuchiya ◽  
Maki Mizogami
Keyword(s):  
Lipid Bilayers ◽  
Local Anesthetics ◽  
Cell Membranes ◽  
Membrane Lipids ◽  
Transmembrane Proteins ◽  
Membrane Lipid ◽  
Direct Inhibition ◽  
Drug Molecules ◽  
Site Of Action ◽  
Lipid Barriers

Despite a long history in medical and dental application, the molecular mechanism and precise site of action are still arguable for local anesthetics. Their effects are considered to be induced by acting on functional proteins, on membrane lipids, or on both. Local anesthetics primarily interact with sodium channels embedded in cell membranes to reduce the excitability of nerve cells and cardiomyocytes or produce a malfunction of the cardiovascular system. However, the membrane protein-interacting theory cannot explain all of the pharmacological and toxicological features of local anesthetics. The administered drug molecules must diffuse through the lipid barriers of nerve sheaths and penetrate into or across the lipid bilayers of cell membranes to reach the acting site on transmembrane proteins. Amphiphilic local anesthetics interact hydrophobically and electrostatically with lipid bilayers and modify their physicochemical property, with the direct inhibition of membrane functions, and with the resultant alteration of the membrane lipid environments surrounding transmembrane proteins and the subsequent protein conformational change, leading to the inhibition of channel functions. We review recent studies on the interaction of local anesthetics with biomembranes consisting of phospholipids and cholesterol. Understanding the membrane interactivity of local anesthetics would provide novel insights into their anesthetic and cardiotoxic effects.

THE STRUCTURE AND FUNCTION OF CELL MEMBRANES

1962 ◽  
Vol 40 (9) ◽  
pp. 1253-1260 ◽  
Author(s):  
A. S. V. Burgen
Keyword(s):  
Cell Membranes ◽  
Membrane Lipid ◽  
Structure And Function ◽  
Membrane Translocation ◽  
And Function

Permeation through cell membranes may occur through solution in membrane lipid, association with carrier molecules, formation of molecular dimers, passage through organized channels or through membrane translocation. It is probable that the predominant mechanism differs according to the type of cell.

Micro-Raman Detection of Nuclear Membrane Lipid Fluctuations in Senescent Epithelial Breast Cancer Cells

2010 ◽  
Vol 82 (10) ◽  
pp. 4259-4263 ◽  
Author(s):  
Melissa M. Mariani ◽  
Lindsey J. Maccoux ◽  
Christian Matthäus ◽  
Max Diem ◽  
Jan G. Hengstler ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Nuclear Membrane ◽  
Breast Cancer Cells ◽  
Membrane Lipid

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.

Ultrastructural change of the cell membranes on myocardium following treatment with H2O2

1993 ◽  
Vol 51 ◽  
pp. 356-357
Author(s):  
Tatsuo Oguro ◽  
Kaoru Aihara ◽  
Kuniharu Aida ◽  
Goro Asano ◽  
Muhammad Ashraf
Keyword(s):  
Cell Membranes ◽  
Culture Medium ◽  
Ultrastructural Change ◽  
Membrane Lipid ◽  
Structure And Function ◽  
Ultrastructural Changes ◽  
Superoxide Anions ◽  
Isolated Hearts ◽  
Rat Hearts ◽  
And Function

It has been suggested that hydrogen peroxide (H2O2) is indirectly associated with postischemicreperfusion injury of the heart. Previously, we reported that the heart was not damaged when perfused with exogenously generated superoxide anions. However, H2O2 which is a dismutation product of superoxide anion severely affected the heart structure and function, and the combined effects of H2O on membrane lipid and proteins result in the formation of membranous bleb.In this study, we evaluated the ultrastructural changes of the cell membranes in isolated rat hearts and cultured myocytes following treatment with exogenous H2O2. In the isolated hearts, 300μM H2O2 was perfused for 15 min and in the isolated cultured myocytes an equal amount of H2O2 was added to the culture medium for 30 min. This dosage of H2O2 was found to be injurious to the heart in our previous study. In the isolated cultured myocytes, 300μM H2O2 was added to the medium for 30 min.

Influence of nuclear membrane lipid fluidity on nuclear RNA release

1979 ◽  
Vol 118 (2) ◽  
pp. 305-309 ◽  
Author(s):  
Gerhard Herlan ◽  
Günter Giese ◽  
Frank Wunderlich
Keyword(s):  
Nuclear Membrane ◽  
Membrane Lipid ◽  
Lipid Fluidity ◽  
Nuclear Rna ◽  
Membrane Lipid Fluidity

THE STRUCTURE AND FUNCTION OF CELL MEMBRANES

1962 ◽  
Vol 40 (1) ◽  
pp. 1253-1260 ◽  
Author(s):  
A. S. V. Burgen
Keyword(s):  
Cell Membranes ◽  
Membrane Lipid ◽  
Structure And Function ◽  
Membrane Translocation ◽  
And Function

Permeation through cell membranes may occur through solution in membrane lipid, association with carrier molecules, formation of molecular dimers, passage through organized channels or through membrane translocation. It is probable that the predominant mechanism differs according to the type of cell.

scholarly journals Expansion and apparent fluidity decrease of nuclear membranes induced by low Ca/Mg. Modulation of nuclear membrane lipid fluidity by the membrane-associated nuclear matrix proteins?

1978 ◽  
Vol 79 (2) ◽  
pp. 479-490 ◽  
Author(s):  
F Wunderlich ◽  
G Giese ◽  
C Bucherer
Keyword(s):  
Electron Microscopy ◽  
Nuclear Envelope ◽  
Nuclear Membrane ◽  
Nuclear Matrix ◽  
Membrane Lipid ◽  
Ion Concentration ◽  
Nuclear Pore ◽  
Lipid Fluidity ◽  
Nuclear Membranes ◽  
Peripheral Layer

Macronuclei isolated from Tetrahymena are contracted in form (average diameter: 10.2 micron) at a final Ca/Mg (3:2)concentration of 5 mM. Lowering the ion concentration to 1 mM induces an expansion of the average nuclear diameter to 12.2 micron. Both contracted and expanded nuclei are surrounded by a largely intact nuclear envelope as revealed by thin-sectioning electron microscopy. Nuclear swelling is accompanied by an expansion of the nuclear envelope as indicated by the decrease in the frequency of nuclear pore complexes from 52.6 to 42.1 pores/micron2 determined by freeze-etch electron microscopy. Contracted nuclear membranes reveal particle-devoid areas (average size: 0.21 micron2) on 59% of their fracture faces at the optimal growth temperature of 28 degrees C. About three-fifths of the number of these smooth areas disappear upon nuclear membrane expansion. Electron spin resonance using 5-doxylstearic acid as a spin label indicates a higher lipid fluidity in contracted than in expa,ded nuclear membranes. Moreover, a thermotropic lipid clustering occurs at approximately 17 degrees C only in expanded nuclear membranes. In contrast to the nuclear membrane-bound lipids, free lipids extracted from the nuclei rigidify with increasing Ca/Mg concentrations. Our findings are compatible with the view that the peripheral layer of the fundamental nuclear protein-framework, the so-called nuclear matrix, can modulate, inter alia, the lipid distribution and fluidity, respectively, in nuclear membranes. We suggest that a contraction of the nuclear matrix's peripheral layer induces a contraction of the nuclear membranes which, in turn, leads to an isothermic lateral lipid segregation within nuclear membranes.

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