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

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

Author Casadei, Bruna R. Google Scholar
Domingues, Cleyton C. Google Scholar
Paula, Eneida de Google Scholar
Riske, Karin do Amaral Autor UNIFESP Google Scholar
Institution Universidade Estadual de Campinas (UNICAMP)
Universidade Federal de São Paulo (UNIFESP)
Abstract 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.
Language English
Sponsor Brazilian Research foundations
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Grant number FAPESP: 2009/0904-1
FAPESP: 2012/10442-8
FAPESP: 2010/18516-5
CNPq: 479993/2011-4
CNPq: 472054/2011-2
Date 2014-06-03
Published in Biophysical Journal. Cambridge: Cell Press, v. 106, n. 11, p. 2417-2425, 2014.
ISSN 0006-3495 (Sherpa/Romeo, impact factor)
Publisher Cell Press
Extent 2417-2425
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000337012300015

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