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The intriguing role of rhamnolipids on plasma membrane remodelling: From lipid rafts to membrane budding
- Source :
- Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual), Universidade de São Paulo (USP), instacron:USP
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- Rhamnolipids (RLs) comprise a class of glycolipids produced by Pseudomonas aeruginosa under appropriate culture medium. They act as biosurfactants being composed by a hydrophilic head of either one (mono-RL) or two (di-RL) rhamnose moieties coupled to hydroxyaliphatic chains. It is well accepted that RLs present low biolitic activity as compared to other synthetic surfactants. However, their mechanisms of action in biological systems are not well defined yet. The interaction of RLs with lipid bilayers are here investigated to address how they impact on plasma membrane at molecular level. Our experimental approach was based on a deep analysis of optical microscopy data from giant unilamellar vesicles (GUVs) dispersed in aqueous solutions containing up to 0.5 mM of commercially available RLs (a mixture of mono-RL, 33ā37 mol%, and di-RL, 63ā67 mol%, cmc of 0.068 ± 0.005 mM). GUVs were made up of a single lipid POPC and a ternary system containing DOPC, sphingomyelin and cholesterol, which mimic lipid raft platforms. Our results demonstrate that RLs have a low partition in the lipid bilayer in respect to the total molecules in solution. We suppose that RLs insert in the outer leaflet with low propensity to flip-flop. In the case of POPC GUVs, the insertion of RL molecules in the outer leaflet impairs changes in spontaneous membrane curvature with incubation time. Then, small buds are formed that remain linked to the original membrane. No changes in membrane permeability have been detected. A remarkable result refers to the insertion of RLs in membranes containing liquid ordered ( L o ) - liquid disordered ( L d ) phase coexistence. The rate of interaction has been observed to be higher for L d phase than for L o phase ( 0.12 · 10 - 6 sā1 and 0.023 · 10 - 6 sā1 for L d and L o , respectively, at RL concentration of 0.5 mM). As a consequence, the preferential RL insertion in L d phase may also alter the membrane spontaneous curvature which, coupled to the change in the line tension associated to the domains boundary, conducted to L o domain protrusion. Even if it has been observed on a model system, such membrane remodelling might correlate to endocytic processes activated in cell membranes, regardless of the participation of specific proteins. Further, changes imposed by RLs in lipid rafts may affect the association of key proteins enrolled in cell signaling, which may perturb cell homeostasis.
- Subjects :
- Membrane permeability
Lipid Bilayers
02 engineering and technology
010402 general chemistry
01 natural sciences
Biomaterials
chemistry.chemical_compound
Membrane Microdomains
Colloid and Surface Chemistry
HOMEOSTASE
Lipid bilayer
POPC
Lipid raft
Chemistry
Vesicle
Cell Membrane
Membrane budding
021001 nanoscience & nanotechnology
0104 chemical sciences
Surfaces, Coatings and Films
Electronic, Optical and Magnetic Materials
Membrane
Membrane curvature
Biophysics
lipids (amino acids, peptides, and proteins)
Glycolipids
0210 nano-technology
Subjects
Details
- ISSN :
- 00219797
- Volume :
- 582
- Database :
- OpenAIRE
- Journal :
- Journal of Colloid and Interface Science
- Accession number :
- edsair.doi.dedup.....ed98e20c207752e7d3fc400cb19033c6