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Lipid Cosorting Mediated by Shiga Toxin Induced Tubulation
Author(s) -
Safouane Mahassine,
Berland Ludwig,
CallanJones Andrew,
Sorre Benoit,
Römer Winfried,
Johannes Ludger,
Toombes Gilman E. S.,
Bassereau Patricia
Publication year - 2010
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2010.01116.x
Subject(s) - sphingolipid , biology , microbiology and biotechnology , globotriaosylceramide , glycosphingolipid , shiga toxin , vesicle , membrane lipids , ceramide , membrane , lipid microdomain , biophysics , cell membrane , biochemistry , fabry disease , medicine , apoptosis , disease , pathology , virulence , gene
To maintain cell membrane homeostasis, lipids must be dynamically redistributed during the formation of transport intermediates, but the mechanisms driving lipid sorting are not yet fully understood. Lowering sphingolipid concentration can reduce the bending energy of a membrane, and this effect could account for sphingolipid depletion along the retrograde pathway. However, sphingolipids and cholesterol are enriched along the anterograde pathway, implying that other lipid sorting mechanisms, such as protein‐mediated sorting, can dominate. To characterize the influence of protein binding on the lipid composition of highly curved membranes, we studied the interactions of the B‐subunit of Shiga toxin (STxB) with giant unilamellar vesicles containing its glycosphingolipid receptor [globotriaosylceramide (Gb3)]. STxB binding induced the formation of tubular membrane invaginations, and fluorescence microscopy images of these highly curved membranes were consistent with co‐enrichment of Gb3 and sphingolipids. In agreement with theory, sorting was stronger for membrane compositions close to demixing. These results strongly support the hypothesis that proteins can indirectly mediate the sorting of lipids into highly curved transport intermediates via interactions between lipids and the membrane receptor of the protein.