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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Direct Visualization of the Action of Triton X-100 on Giant Vesicles of Erythrocyte Membrane Lipids

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Casadei, Bruna R. [1] ; Domingues, Cleyton C. [1] ; de Paula, Eneida [1] ; Riske, Karin A. [2]
Total Authors: 4
[1] Univ Estadual Campinas, Inst Biol, Dept Bioquim, Campinas, SP - Brazil
[2] Univ Fed Sao Paulo, Dept Biofis, Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: BIOPHYSICAL JOURNAL; v. 106, n. 11, p. 2417-2425, JUN 3 2014.
Web of Science Citations: 16

The raft hypothesis proposes that microdomains enriched in sphingolipids, cholesterol, and specific proteins are transiently formed to accomplish important cellular tasks. Equivocally, detergent-resistant membranes were initially assumed to be identical to membrane rafts, because of similarities between their compositions. In fact, the impact of detergents in membrane organization is still controversial. Here, we use phase contrast and fluorescence microscopy to observe giant unilamellar vesicles (GUVs) made of erythrocyte membrane lipids (erythro-GUVs) when exposed to the detergent Triton X-100 (TX-100). We clearly show that TX-100 has a restructuring action on biomembranes. Contact with TX-100 readily induces domain formation on the previously homogeneous membrane of erythro-GUVs at physiological and room temperatures. The shape and dynamics of the formed domains point to liquid-ordered/liquid-disordered (Lo/Ld) phase separation, typically found in raft-like ternary lipid mixtures. The Ld domains are then separated from the original vesicle and completely solubilized by TX-100. The insoluble vesicle left, in the Lo phase, represents around 2/3 of the original vesicle surface at room temperature and decreases to almost 1/2 at physiological temperature. This chain of events could be entirely reproduced with biomimetic GUVs of a simple ternary lipid mixture, 2:1:2 POPC/SM/chol (phosphatidylcholine/sphyngonnyelin/cholesterol), showing that this behavior will arise because of fundamental physicochemical properties of simple lipid mixtures. This work provides direct visualization of TX-100-induced domain formation followed by selective (Ld phase) solubilization in a model system with a complex biological lipid composition. (AU)

FAPESP's process: 10/18516-5 - Caracterization of erythrocyte membrane domains obtained with or without detergent
Grantee:Cleyton Crepaldi Domingues
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 12/10442-8 - Perturbations on charged lipid bilayers induced by electric pulses, antimicrobial peptides and vesicles with opposite charge
Grantee:Karin Do Amaral Riske
Support Opportunities: Regular Research Grants