Molecular Origin of Spatiotemporal Heterogeneity in Biomembranes With Coexisting Liquid Phases: Insights From Topological Rearrangements and Lipid Packing Defects

2018 ◽  
pp. 87-114 ◽  
Author(s):  
Madhusmita Tripathy ◽  
Sahithya S. Iyer ◽  
Anand Srivastava
Keyword(s):  
Lipid Packing ◽  
Liquid Phases ◽  
Packing Defects ◽  
Molecular Origin ◽  
Spatiotemporal Heterogeneity

scholarly journals Lipid packing defects and membrane charge control RAB GTPase recruitment

Traffic ◽  
2018 ◽  
Vol 19 (7) ◽  
pp. 536-545 ◽  
Author(s):  
Guillaume Kulakowski ◽  
Hugo Bousquet ◽  
Jean-Baptiste Manneville ◽  
Patricia Bassereau ◽  
Bruno Goud ◽  
...  
Keyword(s):  
Rab Gtpase ◽  
Lipid Packing ◽  
Charge Control ◽  
Membrane Charge ◽  
Packing Defects

scholarly journals Methyl-branched lipids promote the membrane adsorption of α-synuclein by enhancing shallow lipid-packing defects

2015 ◽  
Vol 17 (24) ◽  
pp. 15589-15597 ◽  
Author(s):  
Matthias Garten ◽  
Coline Prévost ◽  
Clotilde Cadart ◽  
Romain Gautier ◽  
Luc Bousset ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Alpha Synuclein ◽  
Giant Unilamellar Vesicles ◽  
Unilamellar Vesicles ◽  
Lipid Packing ◽  
Packing Defects ◽  
Dynamics Simulations ◽  
Flat Membranes

Reconstitution experiments on Giant Unilamellar Vesicles and Molecular Dynamics Simulations indicate that alpha-synuclein binds to neutral flat membranes in the presence of methyl-branched lipids.

scholarly journals 3D Packing Defects in Lipid Membrane as a Function of Membrane Order

2019 ◽  
Author(s):  
Madhusmita Tripathy ◽  
Anand Srivastava
Keyword(s):  
Lipid Membrane ◽  
Membrane Binding ◽  
Computationally Efficient ◽  
Protein Motifs ◽  
Liquid Phases ◽  
Preferential Localization ◽  
Peripheral Proteins ◽  
Packing Defects ◽  
3D Packing ◽  
Key Steps

AbstractLipid membrane packing defects are considered as essential parameter that regulates specific membrane binding of several peripheral proteins. In absence of direct experimental characterization, lipid packing defects and their role in the binding of peripheral proteins are generally investigated through computational studies, which have been immensely successful in unraveling the key steps of the membrane-binding process. However, packing defects are calculated using 2-dimensional projections and the crucial information on their depths is generally overlooked. Here we present a simple yet computationally efficient algorithm, which identifies these defects in 3-dimensions. We employ the algorithm to understand the nature of packing defects in flat bilayer membranes exhibiting liquid-ordered (Lo), liquid-disordered (Ld) and co-existing Lo/Ld phases. Our results indicate the presence of shallower and smaller defects in the Lo phase membranes as compared to the defects in Ld and mixed Lo/Ld phase membranes. Such analyses can elucidate the molecular scale mechanisms that drive the preferential localization of certain proteins to either of the liquid phases or their interface. Moreover, on the methodology front, our analyses suggest that the projection based 2-dimensional calculation of packing defects might result in inaccurate quantification of their sizes - a very important feature for membrane association of protein motifs, thus advocating the importance of the 3-dimensional calculations.

scholarly journals A filter at the entrance of the Golgi that selects vesicles according to size and bulk lipid composition

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Maud Magdeleine ◽  
Romain Gautier ◽  
Pierre Gounon ◽  
Hélène Barelli ◽  
Stefano Vanni ◽  
...  
Keyword(s):  
Lipid Composition ◽  
Small Radius ◽  
Phosphatidylcholine Liposomes ◽  
Hydrophobic Residues ◽  
Lipid Packing ◽  
Transport Vesicles ◽  
Packing Defects ◽  
The Alps ◽  
Curved Membranes

When small phosphatidylcholine liposomes are added to perforated cells, they bind preferentially to the Golgi suggesting an exceptional avidity of this organelle for curved membranes without stereospecific interactions. We show that the cis golgin GMAP-210 accounts for this property. First, the liposome tethering properties of the Golgi resembles that of the amphipathic lipid-packing sensor (ALPS) motif of GMAP-210: both preferred small (radius < 40 nm) liposomes made of monounsaturated but not saturated lipids. Second, reducing GMAP-210 levels or redirecting its ALPS motif to mitochondria decreased liposome capture by the Golgi. Extensive mutagenesis analysis suggests that GMAP-210 tethers authentic transport vesicles via the same mechanism whereby the ALPS motif senses lipid-packing defects at the vesicle surface through its regularly spaced hydrophobic residues. We conclude that the Golgi uses GMAP-210 as a filter to select transport vesicles according to their size and bulk lipid composition.

scholarly journals Effect of Cholesterol on Membrane Partitioning Dynamics of Hepatitis A Virus-2B peptide

2020 ◽  
Author(s):  
Samapan Sikdar ◽  
Manidipa Banerjee ◽  
Satyavani Vemparala
Keyword(s):  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Membrane Lipid ◽  
Membrane Composition ◽  
Host Cell Membrane ◽  
Detection Mechanism ◽  
Lipid Packing ◽  
Viral Peptide ◽  
Host Membrane ◽  
Packing Defects

ABSTRACTUnderstanding the viral peptide detection, partitioning and subsequent host membrane composition-based response is required for gaining insights into viral mechanism. Here, we probe the crucial role of presence of membrane lipid packing defects, depending on the membrane composition, in allowing the viral peptide belonging to C-terminal Hepatitis A Virus-2B (HAV-2B) to detect, attach and subsequently partition into the host cell membrane mimics. We conclusively show that the hydrophobic residues in the viral peptide detect the transiently present lipid packing defects, insert themselves into such defects, form anchor points and facilitate the partitioning of the peptide. We also show that the presence of cholesterol significantly alters such lipid packing defects, both in size and in number, thus mitigating the partitioning of the membrane active viral peptide into cholesterol-rich membranes. These results show differential ways in which presence and absence of cholesterol can alter the permeability of the host membranes to the membrane active viral peptide component of HAV-2B virus, via lipid packing defects, and can possibly be a part of general membrane detection mechanism for the viroporin class of viruses.

scholarly journals α-Synuclein Senses Lipid Packing Defects and Induces Lateral Expansion of Lipids Leading to Membrane Remodeling

2013 ◽  
Vol 288 (29) ◽  
pp. 20883-20895 ◽  
Author(s):  
Myriam M. Ouberai ◽  
Juan Wang ◽  
Marcus J. Swann ◽  
Celine Galvagnion ◽  
Tim Guilliams ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Binding Mode ◽  
Lateral Expansion ◽  
Optical Biosensing ◽  
Lipid Packing ◽  
Force Microscopy ◽  
Packing Defects ◽  
Lipid Environment ◽  
Dynamic Structures

There is increasing evidence for the involvement of lipid membranes in both the functional and pathological properties of α-synuclein (α-Syn). Despite many investigations to characterize the binding of α-Syn to membranes, there is still a lack of understanding of the binding mode linking the properties of lipid membranes to α-Syn insertion into these dynamic structures. Using a combination of an optical biosensing technique and in situ atomic force microscopy, we show that the binding strength of α-Syn is related to the specificity of the lipid environment (the lipid chemistry and steric properties within a bilayer structure) and to the ability of the membranes to accommodate and remodel upon the interaction of α-Syn with lipid membranes. We show that this interaction results in the insertion of α-Syn into the region of the headgroups, inducing a lateral expansion of lipid molecules that can progress to further bilayer remodeling, such as membrane thinning and expansion of lipids out of the membrane plane. We provide new insights into the affinity of α-Syn for lipid packing defects found in vesicles of high curvature and in planar membranes with cone-shaped lipids and suggest a comprehensive model of the interaction between α-Syn and lipid bilayers. The ability of α-Syn to sense lipid packing defects and to remodel membrane structure supports its proposed role in vesicle trafficking.

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.

In Memoriam. Professor Stefan ERNST

2015 ◽  
Vol 39 (4) ◽  
pp. 665-666
Author(s):  
Mirosław Chorazewski
Keyword(s):  
Secondary Education ◽  
Primary Education ◽  
Unexpected Death ◽  
Uranyl Compounds ◽  
Liquid Phases ◽  
German Speaking ◽  
In Memoriam ◽  
The University ◽  
Phd Thesis ◽  
Molecular Acoustics

Abstract It is with great sadness that we inform our readers about the recent death of Professor Stefan Ernst. Stefan Ernst was born in Piaśniki, Upper Silesia, on November 03, 1934, to parents of Polish-German descent. His primary education started during the war at a German-speaking school in Wirek and continued in Olesno, where he also got his secondary education. As chemistry studies were not yet available at the University ofWrocław in 1953, he started studying biology and switched to chemistry a year later. He received his master’s degree in chemistry in 1959, as one of the first graduates in that major. Then, he started his work on application of thermodynamics and molecular acoustics in investigation of liquid phases under the guidance of the Prof. Bogusława Jeżowska-Trzebiatowska. On 28 November 1967, he defended his PhD thesis entitled “Association-Dissociation Equilibria and the Structure of Uranyl Compounds in Organic Solvents” at the University of Wrocław. Professor Stefan Ernst was a linguist, a polyglot, a renowned thermodynamisist and a researcher of molecular acoustics. With great regret and shock we have learned of his sudden and unexpected death on August 03, 2014, in a hospital in Kraków.

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