The roles of the diversity of amphipathic lipids in shaping membranes by membrane-shaping proteins

2020 ◽  
Vol 48 (3) ◽  
pp. 837-851
Author(s):  
Manabu Kitamata ◽  
Takehiko Inaba ◽  
Shiro Suetsugu
Keyword(s):  
Fatty Acid ◽  
Lipid Composition ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Membrane Lipids ◽  
Cell Types ◽  
Cellular Lipid ◽  
Head Groups ◽  
Packing Defects ◽  
Membrane Bending

Lipid compositions of cells differ according to cell types and intracellular organelles. Phospholipids are major cell membrane lipids and have hydrophilic head groups and hydrophobic fatty acid tails. The cellular lipid membrane without any protein adapts to spherical shapes, and protein binding to the membrane is thought to be required for shaping the membrane for various cellular events. Until recently, modulation of cellular lipid membranes was initially shown to be mediated by proteins recognizing lipid head groups, including the negatively charged ones of phosphatidylserine and phosphoinositides. Recent studies have shown that the abilities of membrane-deforming proteins are also regulated by the composition of fatty acid tails, which cause different degrees of packing defects. The binding of proteins to cellular lipid membranes is affected by the packing defects, presumably through modulation of their interactions with hydrophobic amino acid residues. Therefore, lipid composition can be characterized by both packing defects and charge density. The lipid composition regarding fatty acid tails affects membrane bending via the proteins with amphipathic helices, including those with the ArfGAP1 lipid packing sensor (ALPS) motif and via membrane-deforming proteins with structural folding, including those with the Bin–Amphiphysin–Rvs167 (BAR) domains. This review focuses on how the fatty acid tails, in combination with the head groups of phospholipids, affect protein-mediated membrane deformation.

scholarly journals Enterococcus faecalis Readily Adapts Membrane Phospholipid Composition to Environmental and Genetic Perturbation

2021 ◽  
Vol 12 ◽  
Author(s):  
Brittni M. Woodall ◽  
John R. Harp ◽  
William T. Brewer ◽  
Eric D. Tague ◽  
Shawn R. Campagna ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Enterococcus Faecalis ◽  
Lipid Composition ◽  
Lipid Membrane ◽  
High Resolution Mass Spectrometry ◽  
Phospholipid Composition ◽  
Specific Gene ◽  
Polar Head ◽  
Head Groups

The bacterial lipid membrane, consisting both of fatty acid (acyl) tails and polar head groups, responds to changing conditions through alteration of either the acyl tails and/or head groups. This plasticity is critical for cell survival as it allows maintenance of both the protective nature of the membrane as well as functioning membrane protein complexes. Bacteria that live in fatty-acid rich environments, such as those found in the human host, can exploit host fatty acids to synthesize their own membranes, in turn, altering their physiology. Enterococcus faecalis is such an organism: it is a commensal of the mammalian intestine where it is exposed to fatty-acid rich bile, as well as a major cause of hospital infections during which it is exposed to fatty acid containing-serum. Within, we employed an untargeted approach to detect the most common phospholipid species of E. faecalis OG1RF via ultra-high performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS). We examined not only how the composition responds upon exposure to host fatty acids but also how deletion of genes predicted to synthesize major polar head groups impact lipid composition. Regardless of genetic background and differing basal lipid composition, all strains were able to alter their lipid composition upon exposure to individual host fatty acids. Specific gene deletion strains, however, had altered survival to membrane damaging agents. Combined, the enterococcal lipidome is highly resilient in response to both genetic and environmental perturbation, likely contributing to stress survival.

Abstract 631: Lipid Composition of Gold Nanoparticle-Templated High-Density Lipoprotein Analogs Dictates Cholesterol Efflux Function

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
R Kannan Mutharasan ◽  
Amritha T Singh ◽  
Kaylin M McMahon ◽  
C Shad Thaxton
Keyword(s):  
Fatty Acid ◽  
Lipid Content ◽  
Lipid Composition ◽  
Reverse Cholesterol Transport ◽  
Cholesterol Efflux ◽  
Lipid Membrane ◽  
Density Lipoprotein ◽  
High Density ◽  
High Density Lipoproteins ◽  
Cholesterol Transport

Background: Reverse cholesterol transport, the process by which cholesterol is effluxed from cells to high-density lipoproteins (HDL) and is delivered to the liver for clearance, is a promising pathway to augment for treatment of atherosclerosis. Though structure-function relationships for nascent, discoidal HDL and cholesterol efflux have been well studied, how the lipid composition of spherical HDL species - which varies in pathophysiological conditions - impacts their ability to mediate cholesterol efflux has not been investigated. Methods and Results: Spherical gold nanoparticles (5 nm) were used to synthesize spherical HDL analogs (HDL-NP) by adding ApoAI protein, and various lipids. With this strategy a panel of HDL-NP varying in lipid content was generated. HDL-NP designs tested include: dipalmitylphosphatidylcholine (DPPC, saturated fatty acid), dioleoylphosphatidylcholine (DOPC, unsaturated fatty acid), sphingomyelin, lysophosphatidylcholine (LPC), and mixtures thereof. All of these species are found in natural HDL. After characterizing protein and lipid stoichiometry of the purified HDL-NP, these HDL-NP designs were tested in the cellular reverse cholesterol transport assay using J774 mouse macrophages. These studies demonstrate that all HDL-NP designs mediate more efflux than equimolar amounts of ApoAI protein control, and further demonstrate that HDL-NP designs incorporating unsaturated phospholipid (DOPC), sphingomyelin, and LPC - each of which can increase disorder in the lipid membrane and thus give rise to opportunity for cholesterol to intercalate and bind - enhance cholesterol efflux compared to saturated phospholipid (DPPC) design. Conclusion: In summary, these results demonstrate that lipid content of HDL-NP - analogs of spherical HDL - dictates cholesterol efflux function, a finding which sheds light on the functional importance of lipid content variation seen in mature, spherical HDL species.

scholarly journals Lipid composition of the isolated rat intestinal microvillus membrane

1968 ◽  
Vol 109 (1) ◽  
pp. 51-59 ◽  
Author(s):  
G. G. Forstner ◽  
K. Tanaka ◽  
K. J. Isselbacher
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Neutral Lipid ◽  
Lipid Composition ◽  
Plasma Membranes ◽  
Membrane Lipids ◽  
Saturated Fatty Acids ◽  
Polar Lipids ◽  
Published Data ◽  
Microvillus Membrane

1. Rat intestinal microvillus plasma membranes were prepared from previously isolated brush borders and the lipid composition was analysed. 2. The molar ratio of cholesterol to phospholipid was greatest in the membranes and closely resembled that reported for myelin. 3. Unesterified cholesterol was the major neutral lipid. However, 30% of the neutral lipid fraction was accounted for by glycerides and fatty acid. 4. Five phospholipid components were identified and measured, including phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, sphingomyelin and lysophosphatidylcholine. Though phosphatidylethanolamine was the chief phospholipid, no plasmalogen was detected. 5. In contrast with other plasma membranes in the rat, the polar lipids of the microvillus membrane were rich in glycolipid. The cholesterol:polar lipid (phospholipid+glycolipid) ratio was about 1:3 for the microvillus membrane. Published data suggest that this ratio resembles that of the liver plasma membrane more closely than myelin or the erythrocyte membrane. 6. The fatty acid composition of membrane lipids was altered markedly by a single feeding of safflower oil. Membrane polar lipids did not contain significantly more saturated fatty acids than cellular polar lipids. Differences in the proportion of some fatty acids in membrane and cellular glycerides were noted. These differences may reflect the presence of specific membrane glycerides.

scholarly journals Intact Membrane Lipids of “Candidatus Nitrosopumilus maritimus,” a Cultivated Representative of the Cosmopolitan Mesophilic Group I Crenarchaeota

2008 ◽  
Vol 74 (8) ◽  
pp. 2433-2440 ◽  
Author(s):  
Stefan Schouten ◽  
Ellen C. Hopmans ◽  
Marianne Baas ◽  
Henry Boumann ◽  
Sonja Standfest ◽  
...  
Keyword(s):  
Polar Lipid ◽  
Lipid Composition ◽  
Membrane Lipids ◽  
Lipid Analysis ◽  
Membrane Lipid ◽  
Membrane Lipid Composition ◽  
The Core ◽  
Group I ◽  
Head Groups ◽  
Intact Membrane

ABSTRACT In this study we analyzed the membrane lipid composition of “Candidatus Nitrosopumilus maritimus,” the only cultivated representative of the cosmopolitan group I crenarchaeota and the only mesophilic isolate of the phylum Crenarchaeota. The core lipids of “Ca. Nitrosopumilus maritimus” consisted of glycerol dialkyl glycerol tetraethers (GDGTs) with zero to four cyclopentyl moieties. Crenarchaeol, a unique GDGT containing a cyclohexyl moiety in addition to four cyclopentyl moieties, was the most abundant GDGT. This confirms unambiguously that crenarchaeol is synthesized by species belonging to the group I.1a crenarchaeota. Intact polar lipid analysis revealed that the GDGTs have hexose, dihexose, and/or phosphohexose head groups. Similar polar lipids were previously found in deeply buried sediments from the Peru margin, suggesting that they were in part synthesized by group I crenarchaeota.

Drug Permeation through Biological Barriers

Drug Delivery ◽  
2001 ◽  
Author(s):  
W. Mark Saltzman
Keyword(s):  
Plasma Membrane ◽  
Lipid Composition ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Average Molecular Weight ◽  
Transport Proteins ◽  
Cross Sectional ◽  
Tissue Properties ◽  
Experimental Systems ◽  
Outer Leaflet

In multicellular organisms, thin lipid membranes serve as semipermeable barriers between aqueous compartments. The plasma membrane of the cell separates the cytoplasm from the extracellular space; endothelial cell membranes separate the blood within the vascular space from the rest of the tissue. Properties of the lipid membrane are critically important in regulating the movement of molecules between these aqueous spaces. While certain barrier properties of membranes can be attributed to the lipid components, accessory molecules within the cell membrane—particularly transport proteins and ion channels—control the rate of permeation of many solutes. Transport proteins permit the cell to regulate the composition of its intracellular environment in response to extracellular conditions. The relationship between membrane structure, membrane function, and cell physiology is an area of active, ongoing study. Our interest here is practical: what are the basic mechanisms of drug movement through membranes and how can one best predict the rate of permeation of an agent through a membrane barrier? To answer that question, this section presents rates of permeation measured in some common experimental systems and models of membrane permeation that can be used for prediction. The external surface of the plasma membrane carries a carbohydrate-rich coat called the glycocalyx; charged groups in the glycocalyx, which are provided principally by carbohydrates containing sialic acid, cause the surface to be negatively charged. On average, the plasma membrane of human cells contains, by mass, 50% protein, 45% lipid, and 5% carbohydrate. Given the mass ratio of protein to lipid is ~ 1 : 1, and assuming reasonable values for the average molecular weight and cross-sectional area for each type of molecule (50 × Mw,lipid = Mw,protein; Alipid = 50 Å2 and Aprotein = 1,000 Å2), the area fraction of protein on a typical membrane is ~ 33%. The lipid composition varies in membranes from different cells depending on the type of cell and its function. In addition, the outermost monolayer of lipids, called the outer leaflet, has a different lipid composition from the inner leaflet.

scholarly journals Erythrocyte Membrane Lipids in Fríedreich's Ataxia

1979 ◽  
Vol 6 (2) ◽  
pp. 291-294 ◽  
Author(s):  
P. Draper ◽  
Y.S. Huang ◽  
D. Shapcott ◽  
B. Lemieux ◽  
M. Brennan ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Composition ◽  
Membrane Lipids ◽  
Fatty Acid Distribution ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia ◽  
Erythrocyte Membranes ◽  
Phospholipid Classes ◽  
Membrane Components ◽  
And Control

SummaryIn a study of the lipid composition of erythrocyte membranes in Friedreich's ataxia, the concentration of the major membrane components (phosr pholipids, cholesterol and protein) in ataxie patients, family members, and control subjects were found to be the same. The total fatty acid distribution was also normal. However, an altered distribution of phospholipid classes in erythrocytes was noted (an increase of PI + PS and a decrease of P E in Friedreich's ataxia patients).

scholarly journals Discrete Conductance Fluctuations in Lipid Bilayer Protein Membranes

1969 ◽  
Vol 53 (6) ◽  
pp. 741-757 ◽  
Author(s):  
R. C. Bean ◽  
W. C. Shepherd ◽  
H. Chan ◽  
Joellen Eichner
Keyword(s):  
Lipid Bilayer ◽  
Lipid Membranes ◽  
Lipid Membrane ◽  
Membrane Lipids ◽  
Initial Reaction ◽  
Lipid Bilayer Membranes ◽  
Conductance Fluctuations ◽  
Excitable Membranes ◽  
Conductance States ◽  
High Conductance

Discrete fluctuations in conductance of lipid bilayer membranes may be observed during the initial stages of membrane interaction with EIM ("excitability inducing material"), during destruction of the EIM conductance by proteolysis, and during the potential-dependent transitions between low and high conductance states in the "excitable" membranes. The discrete conductance steps observed during the initial reaction of EIM with the lipid membranes are remarkably uniform, even in membranes of widely varying lipid composition. They range only from 2 to 6 x 10-10 ohm-1 and average 4 x 10-10 ohm-1. Steps found during destruction of the EIM conductance by proteolysis are somewhat smaller. The transition between high conductance and low conductance states may involve steps as small as 0.5 x 10-10 ohm-1. These phenomena are consistent with the formation of a stable protein bridge across the lipid membrane to provide a polar channel for the transport of cations. T6he uniform conductance fluctuations observed during the formation of these macromolecular channels may indicate that the ions in a conductive channel, in its open state, are largely protected from the influence of the polar groups of the membrane lipids. Potential-dependent changes in conductance may be due to configurational or positional changes in the protein channel. Differences in lipid-lipid and lipid-macromolecule interactions may account for the variations in switching kinetics in various membrane systems.

Feedback between membrane tension, lipid shape and curvature in the formation of packing defects

2018 ◽  
Author(s):  
M. Pinot ◽  
S. Vanni ◽  
E. Ambroggio ◽  
D. Guet ◽  
B. Goud ◽  
...  
Keyword(s):  
Intracellular Transport ◽  
Lipid Membrane ◽  
Membrane Curvature ◽  
Membrane Tension ◽  
Membrane Pore ◽  
Membrane Deformation ◽  
Lipid Packing ◽  
Head Groups ◽  
Packing Defects ◽  
The Alps

AbstractLipid packing defects favor the binding of proteins to cellular membranes by creating spaces between lipid head groups that allow the insertion of amphipathic helices or lipid modifications. The density of packing defects in a lipid membrane is well known to increase with membrane curvature and in the presence of conical-shaped lipids. In contrast, the role of membrane tension in the formation of lipid packing defects has been poorly investigated. Here we use a combination of numerical simulations and experiments to measure the effect of membrane tension on the density of lipid packing defects. We first monitor the binding of ALPS (amphipathic lipid packing sensor) to giant unilamellar vesicles and observe a striking periodic binding of ALPS that we attribute to osmotically-induced membrane tension and transient membrane pore formation. Using micropipette aspiration experiments, we show that a high membrane tension induces a reversible increase in the density of lipid packing defects. We next focus on packing defects induced by lipid shape and show that conical lipids generate packing defects similar to that induced by membrane tension and enhance membrane deformation due to the insertion of the ALPS helix. Both cyclic ALPS binding and the cooperative effect of ALPS binding and conical lipids on membrane deformation result from an interplay between helix insertion and lipid packing defects created by membrane tension, conical lipids and/or membrane curvature. We propose that feedback mechanisms involving membrane tension, lipid shape and membrane curvature play a crucial role in membrane deformation and intracellular transport events.

Cytoplasmic membrane of Rhizobium meliloti bacteroids. I. Alterations in lipid composition, physical properties, and respiratory proteins

1983 ◽  
Vol 61 (12) ◽  
pp. 1334-1340 ◽  
Author(s):  
R. W. Miller ◽  
P. A. Tremblay
Keyword(s):  
Fatty Acid ◽  
Physical Properties ◽  
Lipid Composition ◽  
Cytoplasmic Membrane ◽  
Membrane Lipids ◽  
Rhizobium Meliloti ◽  
Root Nodules ◽  
Reducing Power ◽  
Spin Resonance ◽  
And Function

Differentiation of Rhizobium meliloti cells in alfalfa root nodules is characterized by alteration in the lipid composition and physical properties of the bacteroid cytoplasmic membrane. Nitrogen-fixing bacteroids isolated from nodules showed an altered phospholipid and fatty acid composition and lacked aliphatic alcohols normally associated with the bacterial cell wall. Bacteroid cytoplasmic membrane lipids were more fluid, but responded specifically to the presence of calcium ion with an increase in the ordered packing of fatty acid side chains, as determined from electron spin resonance spectra of spin probes intercalated in the membrane. This cation also specifically enhanced rates of respiration of the bacteroids and rates of reduction of the spin probe. Bacteroid cytoplasmic membranes differed from those of air-grown cells, both in the amount of cytochromes b and c per cell and in the nature of the terminal oxidase. Cytochrome aa3, was present in bacteroids at less than 1/10 the level found in air-grown cells. The observed differences in the structure and function of the cytoplasmic membrane of bacteroids may be associated with requirements of the bacterial symbiont for utilization of carbon substrates and provision of reducing power in support of the nitrogenase enzyme system which is expressed in the nodule environment.

The organization of cell surface membrane domains

1989 ◽  
Vol 47 ◽  
pp. 804-805
Author(s):  
Michael Edidin
Keyword(s):  
Cell Surface ◽  
Membrane Lipids ◽  
Surface Membrane ◽  
Lateral Diffusion ◽  
Cell Types ◽  
Membrane Domains ◽  
Membrane Biology ◽  
Morphological Polarity ◽  
Discrete Domains ◽  
Membrane Components

Cell surface membranes are based on a fluid lipid bilayer and models of the membranes' organization have emphasised the possibilities for lateral motion of membrane lipids and proteins within the bilayer. Two recent trends in cell and membrane biology make us consider ways in which membrane organization works against its inherent fluidity, localizing both lipids and proteins into discrete domains. There is evidence for such domains, even in cells without obvious morphological polarity and organization [Table 1]. Cells that are morphologically polarised, for example epithelial cells, raise the issue of membrane domains in an accute form.The technique of fluorescence photobleaching and recovery, FPR, was developed to measure lateral diffusion of membrane components. It has also proven to be a powerful tool for the analysis of constraints to lateral mobility. FPR resolves several sorts of membrane domains, all on the micrometer scale, in several different cell types.

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