The intriguing role of rhamnolipids on plasma membrane remodelling
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2021
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Journal of Colloid and Interface Science
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Resumo
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, 33–37 mol%, and di-RL, 63–67 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 (Lo) - liquid disordered
(Ld) phase coexistence. The rate of interaction has been observed to be higher for Ld phase than for Lo
phase (0:12 . 10-6 s-1 and 0:023 . 10-6 s-1 for Ld and Lo, respectively, at RL concentration of 0.5 mM).
As a consequence, the preferential RL insertion in Ld phase may also alter the membrane spontaneous curvature which, coupled to the change in the line tension associated to the domains boundary, conducted
to Lo 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.
Como referenciar
COME, BENEDETTA; DONATO, MARESSA; POTENZA, LUCIA F.; MARIANI, PAOLO; ITRI, ROSANGELA; SPINOZZI, FRANCESCO. The intriguing role of rhamnolipids on plasma membrane remodelling: from lipid rafts to membrane budding. Journal of Colloid and Interface Science, v. 582, n. Part B, p. 669-677, 2021. DOI: 10.1016/j.jcis.2020.08.027. Disponível em: http://200.136.52.105/handle/123456789/31623. Acesso em: 23 Apr 2024.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.