scholarly journals The role of membrane curvature for the wrapping of nanoparticles

Soft Matter ◽  
2016 ◽  
Vol 12 (2) ◽  
pp. 581-587 ◽  
Author(s):  
Amir Houshang Bahrami ◽  
Reinhard Lipowsky ◽  
Thomas R. Weikl
Keyword(s):  
Membrane Curvature

Energetic barriers for wrapping arise if the membrane initially bulges towards the nanoparticle. In contrast, stable partially wrapped states occur if the membrane initially bulges away from the nanoparticle.

scholarly journals The role of membrane curvature elastic stress for function of rhodopsin-like G protein-coupled receptors

Biochimie ◽  
2014 ◽  
Vol 107 ◽  
pp. 28-32 ◽  
Author(s):  
Olivier Soubias ◽  
Walter E. Teague ◽  
Kirk G. Hines ◽  
Klaus Gawrisch
Keyword(s):  
G Protein ◽  
Elastic Stress ◽  
Membrane Curvature ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled

scholarly journals The plasma membrane as a mechanochemical transducer

2019 ◽  
Vol 374 (1779) ◽  
pp. 20180221 ◽  
Author(s):  
Anabel-Lise Le Roux ◽  
Xarxa Quiroga ◽  
Nikhil Walani ◽  
Marino Arroyo ◽  
Pere Roca-Cusachs
Keyword(s):  
Plasma Membrane ◽  
Cellular Response ◽  
Mechanical Response ◽  
Membrane Curvature ◽  
Mechanical Stresses ◽  
Mechanical Stimuli ◽  
Biochemical Responses ◽  
Interdisciplinary Approaches ◽  
Mechanochemical Transduction

Cells are constantly submitted to external mechanical stresses, which they must withstand and respond to. By forming a physical boundary between cells and their environment that is also a biochemical platform, the plasma membrane (PM) is a key interface mediating both cellular response to mechanical stimuli, and subsequent biochemical responses. Here, we review the role of the PM as a mechanosensing structure. We first analyse how the PM responds to mechanical stresses, and then discuss how this mechanical response triggers downstream biochemical responses. The molecular players involved in PM mechanochemical transduction include sensors of membrane unfolding, membrane tension, membrane curvature or membrane domain rearrangement. These sensors trigger signalling cascades fundamental both in healthy scenarios and in diseases such as cancer, which cells harness to maintain integrity, keep or restore homeostasis and adapt to their external environment. This article is part of a discussion meeting issue ‘Forces in cancer: interdisciplinary approaches in tumour mechanobiology’.

Membrane Curvature Induced by Sugar and Polymer Solutions

1997 ◽  
Vol 489 ◽  
Author(s):  
H.-G. Döbereiner ◽  
A. Lehmann ◽  
W. Goedel ◽  
O. Selchow ◽  
R. Lipowsky
Keyword(s):  
Polymer Solutions ◽  
Lipid Vesicles ◽  
Membrane Curvature ◽  
Elastic Membrane ◽  
Spontaneous Curvature ◽  
Membrane Asymmetry ◽  
Bending Modulus ◽  
Bending Elasticity ◽  
Cellular Organelles

AbstractWe monitor the effect of transversal membrane asymmetry on the morphology of giant uni-lamellar vesicles in sugar and polymer solutions. The shapes of fluid lipid vesicles are governed by the bending elasticity of their membrane which is characterized by the bending modulus and the spontaneous curvature of the bilayer. We present a recently developed technique for the measurement of the spontaneous curvature using quantitative phase contrast microscopy. Different mechanisms for elastic membrane asymmetry and the role of the bending energy concept for the morphology of cellular organelles are discussed.

Substrate delivery mechanism and the role of membrane curvature in factor X activation by extrinsic tenase

2017 ◽  
Vol 435 ◽  
pp. 125-133 ◽  
Author(s):  
Tatiana A. Kovalenko ◽  
Mikhail A. Panteleev ◽  
Anastasia N. Sveshnikova
Keyword(s):  
Membrane Curvature ◽  
Factor X ◽  
Delivery Mechanism ◽  
Factor X Activation

scholarly journals Sphingomyelin metabolism controls the shape and function of the Golgi cisternae

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Felix Campelo ◽  
Josse van Galen ◽  
Gabriele Turacchio ◽  
Seetharaman Parashuraman ◽  
Michael M Kozlov ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Structural Organization ◽  
Structural Features ◽  
Membrane Curvature ◽  
Eukaryotic Cells ◽  
Golgi Cisterna ◽  
Golgi Membranes ◽  
And Function ◽  
Flat Cisternae

The flat Golgi cisterna is a highly conserved feature of eukaryotic cells, but how is this morphology achieved and is it related to its function in cargo sorting and export? A physical model of cisterna morphology led us to propose that sphingomyelin (SM) metabolism at the trans-Golgi membranes in mammalian cells essentially controls the structural features of a Golgi cisterna by regulating its association to curvature-generating proteins. An experimental test of this hypothesis revealed that affecting SM homeostasis converted flat cisternae into highly curled membranes with a concomitant dissociation of membrane curvature-generating proteins. These data lend support to our hypothesis that SM metabolism controls the structural organization of a Golgi cisterna. Together with our previously presented role of SM in controlling the location of proteins involved in glycosylation and vesicle formation, our data reveal the significance of SM metabolism in the structural organization and function of Golgi cisternae.

scholarly journals Deformation of membrane vesicles due to chiral surface proteins

2021 ◽  
Author(s):  
Arabinda Behera ◽  
Gaurav Kumar ◽  
Sk Ashif Akram ◽  
Anirban Sain
Keyword(s):  
Membrane Vesicles ◽  
Membrane Curvature ◽  
Surface Proteins ◽  
Triangulated Surface ◽  
Chiral Nematic ◽  
Mc Simulation ◽  
Chiral Interaction ◽  
Fixed Cylinder ◽  
Chiral Surface

Chiral, rod-like molecules can self-assemble into cylindrical membrane tubules and helical ribbons. They have been successfully modeled using the theory of chiral nematics. Models have also predicted the role of chiral lipids in forming nanometer-sized membrane buds in the cell. However, in most theoretical studies, the membrane shapes are considered fixed (cylinder, sphere, saddle, etc.), and their optimum radius of curvatures are found variationally by minimizing the energy of the composite system consisting of membrane and chiral nematics. Numerical simulations have only recently started to consider membrane deformation and chiral orientation simultaneously. Here we examine how deformable, closed membrane vesicles and chiral nematic rods mutually influence each other's shape and orientation, respectively, using Monte-Carlo (MC) simulation on a closed triangulated surface. For this, we adopt a discrete form of chiral interaction between rods, originally proposed by Van der Meer et al. (1976) for off-lattice simulations. In our simulation, both conical and short cylindrical tubules emerge, depending on the strength of the chiral interaction and the intrinsic chirality of the molecules. We show that the Helfrich-Prost term, which couple nematic tilt with local membrane curvature in continuum models, can account for most of the observations in the simulation. At higher chirality, our theory also predicts chiral tweed phase on cones, with varying bandwidths.

scholarly journals Aberrant Membrane Composition and Biophysical Properties Impair Erythrocyte Morphology and Functionality in Elliptocytosis

Biomolecules ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1120
Author(s):  
Hélène Pollet ◽  
Anne-Sophie Cloos ◽  
Amaury Stommen ◽  
Juliette Vanderroost ◽  
Louise Conrard ◽  
...  
Keyword(s):  
Cholesterol Content ◽  
Membrane Curvature ◽  
Acid Sphingomyelinase ◽  
Cholesterol Depletion ◽  
Membrane Composition ◽  
Biophysical Properties ◽  
Erythrocyte Morphology ◽  
Lipid Domain ◽  
Functional Consequences

Red blood cell (RBC) deformability is altered in inherited RBC disorders but the mechanism behind this is poorly understood. Here, we explored the molecular, biophysical, morphological, and functional consequences of α-spectrin mutations in a patient with hereditary elliptocytosis (pEl) almost exclusively expressing the Pro260 variant of SPTA1 and her mother (pElm), heterozygous for this mutation. At the molecular level, the pEI RBC proteome was globally preserved but spectrin density at cell edges was increased. Decreased phosphatidylserine vs. increased lysophosphatidylserine species, and enhanced lipid peroxidation, methemoglobin, and plasma acid sphingomyelinase (aSMase) activity were observed. At the biophysical level, although membrane transversal asymmetry was preserved, curvature at RBC edges and rigidity were increased. Lipid domains were altered for membrane:cytoskeleton anchorage, cholesterol content and response to Ca2+ exchange stimulation. At the morphological and functional levels, pEl RBCs exhibited reduced size and circularity, increased fragility and impaired membrane Ca2+ exchanges. The contribution of increased membrane curvature to the pEl phenotype was shown by mechanistic experiments in healthy RBCs upon lysophosphatidylserine membrane insertion. The role of lipid domain defects was proved by cholesterol depletion and aSMase inhibition in pEl. The data indicate that aberrant membrane content and biophysical properties alter pEl RBC morphology and functionality.

scholarly journals The Mason-Pfizer Monkey Virus PPPY and PSAP Motifs Both Contribute to Virus Release

2003 ◽  
Vol 77 (17) ◽  
pp. 9474-9485 ◽  
Author(s):  
Eva Gottwein ◽  
Jochen Bodem ◽  
Barbara Müller ◽  
Ariane Schmechel ◽  
Hanswalter Zentgraf ◽  
...  
Keyword(s):  
Cellular Protein ◽  
Membrane Curvature ◽  
Mutant Virus ◽  
Dependent Manner ◽  
Virus Release ◽  
Immunodeficiency Virus ◽  
Ptap Motif ◽  
Hiv 1

ABSTRACT Late (L) domains are required for the efficient release of several groups of enveloped viruses. Three amino acid motifs have been shown to provide L-domain function, namely, PPXY, PT/SAP, or YPDL. The retrovirus Mason-Pfizer monkey virus (MPMV) carries closely spaced PPPY and PSAP motifs. Mutation of the PPPY motif results in a complete loss of virus release. Here, we show that the PSAP motif acts as an additional L domain and promotes the efficient release of MPMV but requires an intact PPPY motif to perform its function. Examination of HeLaP4 cells expressing PSAP mutant virus by electron microscopy revealed mostly late budding structures and chains of viruses accumulating at the cell surface with little free virus. In the case of the PPPY mutant virus, budding appeared to be mostly arrested at an earlier stage before induction of membrane curvature. The cellular protein TSG101, which interacts with the human immunodeficiency virus type 1 (HIV-1) PTAP L domain, was packaged into MPMV in a PSAP-dependent manner. Since TSG101 is crucial for HIV-1 release, this result suggests that the Gag-TSG101 interaction is responsible for the virus release function of the MPMV PSAP motif. Nedd4, which has been shown to interact with viral PPPY motifs, was also detected in MPMV particles, albeit at much lower levels. Consistent with a role of VPS4A in the budding of both PPPY and PTAP motif-containing viruses, the overexpression of ATPase-defective GFP-VPS4A fusion proteins blocked both wild-type and PSAP mutant virus release.

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