Role of Water in the Hydration Force Acting between Lipid Bilayers

Langmuir ◽  
1996 ◽  
Vol 12 (11) ◽  
pp. 2625-2629 ◽  
Author(s):  
Lalith Perera ◽  
Ulrich Essmann ◽  
Max L. Berkowitz
Keyword(s):  
Lipid Bilayers ◽  
Hydration Force

scholarly journals Lipid Transporters Beam Signals from Cell Membranes

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 562
Author(s):  
Miliça Ristovski ◽  
Danny Farhat ◽  
Shelly Ellaine M. Bancud ◽  
Jyh-Yeuan Lee
Keyword(s):  
Membrane Proteins ◽  
Lipid Bilayers ◽  
Lipid Composition ◽  
Structural Integrity ◽  
Current Knowledge ◽  
Integral Membrane Proteins ◽  
Cellular Membranes ◽  
Cytoplasmic Proteins ◽  
Lipid Transporters

Lipid composition in cellular membranes plays an important role in maintaining the structural integrity of cells and in regulating cellular signaling that controls functions of both membrane-anchored and cytoplasmic proteins. ATP-dependent ABC and P4-ATPase lipid transporters, two integral membrane proteins, are known to contribute to lipid translocation across the lipid bilayers on the cellular membranes. In this review, we will highlight current knowledge about the role of cholesterol and phospholipids of cellular membranes in regulating cell signaling and how lipid transporters participate this process.

scholarly journals Adsorption of α-Synuclein to Supported Lipid Bilayers: Positioning and Role of Electrostatics

2013 ◽  
Vol 4 (10) ◽  
pp. 1339-1351 ◽  
Author(s):  
Erik Hellstrand ◽  
Marie Grey ◽  
Marie-Louise Ainalem ◽  
John Ankner ◽  
V. Trevor Forsyth ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Supported Lipid Bilayers

Role of cholesterol flip-flop in oxidized lipid bilayers

2021 ◽  
Author(s):  
Phansiri Boonnoy ◽  
Viwan Jarerattanachat ◽  
Mikko Karttunen ◽  
Jirasak Wong-ekkabut
Keyword(s):  
Lipid Bilayers ◽  
Flip Flop

scholarly journals Cryo-EM structures of the DCPIB-inhibited volume-regulated anion channel LRRC8A in lipid nanodiscs

2018 ◽  
Author(s):  
David M. Kern ◽  
SeCheol Oh ◽  
Richard K. Hite ◽  
Stephen G. Brohawn
Keyword(s):  
Lipid Bilayers ◽  
Critical Role ◽  
Anion Channel ◽  
Lipid Binding ◽  
Channel Structure ◽  
Anion Channels ◽  
Cryo Electron Microscopy ◽  
Lipid Nanodiscs ◽  
Insight Into

AbstractHypoosmotic conditions activate volume-regulated anion channels in vertebrate cells. These channels are formed by leucine-rich repeat-containing protein 8 (LRRC8) family members and contain LRRC8A in homo- or hetero-hexameric assemblies. Here we present single-particle cryo-electron microscopy structures of LRRC8A in complex with the inhibitor DCPIB reconstituted in lipid nanodiscs. DCPIB plugs the channel like a cork in a bottle - binding in the extracellular selectivity filter and sterically occluding ion conduction. Constricted and expanded structures reveal coupled dilation of cytoplasmic LRRs and the channel pore, suggesting a mechanism for channel gating by internal stimuli. Conformational and symmetry differences between LRRC8A structures determined in detergent micelles and lipid bilayers related to reorganization of intersubunit lipid binding sites demonstrate a critical role for the membrane in determining channel structure. These results provide insight into LRRC8 gating and inhibition and the role of lipids in the structure of an ionic-strength sensing ion channel.

scholarly journals Role of Liposomes Composite as Drug Transport Mechanism

2021 ◽  
pp. 230-243
Keyword(s):  
Drug Delivery ◽  
Lipid Bilayers ◽  
Transport Mechanism ◽  
Drug Transport ◽  
Phospholipid Bilayer ◽  
Drug Transporter ◽  
Delivery Methods ◽  
Second Stage ◽  
Novel Drug

Liposomes are spherical shaped vesicles comprising of at least one phospholipid bilayer that serve as a novel drug delivery framework. They are microscopic structures in which a fluid system is totally encased by a film made out of lipid bilayers. It varies in size, conformation, charge and drug transporter stacked with assortment of particles, for example, small molecules of drug, plasmids, nucleotides or proteins and so on. Ongoing advances in nanotherapeutics have brought about engineered liposomes rising in nanomedicine, giving better restorative control of diseased states. This has made ready for the improvement of second-stage liposomes for increased efficiency and could at last lead to a change in perspective from the regular drug delivery methods.

scholarly journals The role of surface charge in the interaction of nanoparticles with model pulmonary surfactants

Soft Matter ◽  
2018 ◽  
Vol 14 (28) ◽  
pp. 5764-5774 ◽  
Author(s):  
F. Mousseau ◽  
J.-F. Berret
Keyword(s):  
Surface Charge ◽  
Lipid Bilayers ◽  
Pulmonary Surfactant ◽  
Lipid Vesicles ◽  
Electrostatic Charge ◽  
Supported Lipid Bilayers ◽  
Pulmonary Surfactants ◽  
Inhaled Nanoparticles

Inhaled nanoparticles reaching the respiratory zone in the lungs enter first in contact with the pulmonary surfactant. It is shown here that nanoparticles and lipid vesicles formulated from different surfactant mimetics interact predominantlyviaelectrostatic charge mediated attraction and do not form supported lipid bilayers spontaneously.

scholarly journals Palmitoylated Cysteines in Chikungunya Virus nsP1 Are Critical for Targeting to Cholesterol-Rich Plasma Membrane Microdomains with Functional Consequences for Viral Genome Replication

2020 ◽  
Vol 94 (10) ◽  
Author(s):  
William Bakhache ◽  
Aymeric Neyret ◽  
Eric Bernard ◽  
Andres Merits ◽  
Laurence Briant
Keyword(s):  
Plasma Membrane ◽  
Lipid Bilayers ◽  
Functional Role ◽  
Membrane Microdomains ◽  
Genome Replication ◽  
Functional Importance ◽  
Late Endosomes ◽  
Plasma Membrane Microdomains ◽  
Insight Into

ABSTRACT In mammalian cells, alphavirus replication complexes are anchored to the plasma membrane. This interaction with lipid bilayers is mediated through the viral methyl/guanylyltransferase nsP1 and reinforced by palmitoylation of cysteine residue(s) in the C-terminal region of this protein. Lipid content of membranes supporting nsP1 anchoring remains poorly studied. Here, we explore the membrane binding capacity of nsP1 with regard to cholesterol. Using the medically important chikungunya virus (CHIKV) as a model, we report that nsP1 cosegregates with cholesterol-rich detergent-resistant membrane microdomains (DRMs), also called lipid rafts. In search for the critical factor for cholesterol partitioning, we identify nsP1 palmitoylated cysteines as major players in this process. In cells infected with CHIKV or transfected with CHIKV trans-replicase plasmids, nsP1, together with the other nonstructural proteins, are detected in DRMs. While the functional importance of CHIKV nsP1 preference for cholesterol-rich membrane domains remains to be determined, we observed that U18666A- and imipramine-induced sequestration of cholesterol in late endosomes redirected nsP1 to these compartments and simultaneously dramatically decreased CHIKV genome replication. A parallel study of Sindbis virus (SINV) revealed that nsP1 from this divergent alphavirus displays a low affinity for cholesterol and only moderately segregates with DRMs. Behaviors of CHIKV and SINV with regard to cholesterol, therefore, match with the previously reported differences in the requirement for nsP1 palmitoylation, which is dispensable for SINV but strictly required for CHIKV replication. Altogether, this study highlights the functional importance of nsP1 segregation with DRMs and provides new insight into the functional role of nsP1 palmitoylated cysteines during alphavirus replication. IMPORTANCE Functional alphavirus replication complexes are anchored to the host cell membranes through the interaction of nsP1 with the lipid bilayers. In this work, we investigate the importance of cholesterol for such an association. We show that nsP1 has affinity for cholesterol-rich membrane microdomains formed at the plasma membrane and identify conserved palmitoylated cysteine(s) in nsP1 as the key determinant for cholesterol affinity. We demonstrate that drug-induced cholesterol sequestration in late endosomes not only redirects nsP1 to this compartment but also dramatically decreases genome replication, suggesting the functional importance of nsP1 targeting to cholesterol-rich plasma membrane microdomains. Finally, we show evidence that nsP1 from chikungunya and Sindbis viruses displays different sensitivity to cholesterol sequestering agents that parallel with their difference in the requirement for nsP1 palmitoylation for replication. This research, therefore, gives new insight into the functional role of palmitoylated cysteines in nsP1 for the assembly of functional alphavirus replication complexes in their mammalian host.

Functional identification of a sarcolemmal chloride channel from bovine tracheal smooth muscle

1996 ◽  
Vol 271 (5) ◽  
pp. C1716-C1724 ◽  
Author(s):  
D. Salvail ◽  
A. Alioua ◽  
E. Rousseau
Keyword(s):  
Smooth Muscle ◽  
Lipid Bilayers ◽  
Reversal Potential ◽  
Tracheal Smooth Muscle ◽  
Disulfonic Acid ◽  
Equilibrium Potential ◽  
Functional Identification ◽  
Cl Channels ◽  
Cl Conductance

The biophysical and pharmacological characteristics of unitary Cl- currents from bovine tracheal smooth muscle cells were studied after reconstitution of microsomal vesicles into planar lipid bilayers. Two types of currents were recorded simultaneously in KCl buffer: the well-defined Ca(2+)-dependent K+ conductance [GK(Ca)] and a much smaller Cl- current, indicating that the Cl- channels under scrutiny originate from the same membrane as the GK(Ca)-type channels, the plasma membrane of airway smooth muscle (ASM) cells. The GK(Ca) activities were eliminated by the use of CsCl buffer. The average unitary Cl- conductance measured in 50 mM trans-250 mM cis CsCl was 77 +/- 6 pS (n = 21), and the reversal potential measured in various CsCl gradients followed the Cl- equilibrium potential as determined from the Nernst equation. In contrast with the previous reports describing the Ca2+ sensitivity of macroscopic ASM Cl- currents, this channel was found to be insensitive to cytoplasmic and extracellular Ca2+ levels. Phosphorylation cocktails, including protein kinases A, G, or C, did not alter the activity of the channel nor did changes in pH. Among a series of Cl- channel inhibitors, 4,4'-diisothiocyanostilbene-2, 2'-disulfonic acid [50% effective concentration (EC50) = 30 microM] and 5-nitro-2-(3-phenylpropylamino) benzoic acid (EC50 = 130 microM) were the most potent blockers of the current examined. The exact role of this surface Cl- conductance remains unclear, and its involvement in cellular activity needs further investigation.

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