Lipid Cosorting Mediated by Shiga Toxin Induced Tubulation

Authors

  • Mahassine Safouane,

    1. Institut Curie, Centre de Recherche, Membrane and Cell Functions Group; CNRS UMR168, Physico-Chimie Curie; Université Pierre et Marie Curie, 26 rue d’Ulm, 75248 Paris Cedex 05, France
    Search for more papers by this author
    • These authors contributed equally to this work.

  • Ludwig Berland,

    1. Institut Curie, Centre de Recherche, Membrane and Cell Functions Group; CNRS UMR168, Physico-Chimie Curie; Université Pierre et Marie Curie, 26 rue d’Ulm, 75248 Paris Cedex 05, France
    2. Current address: Department of Biochemistry, University Sciences II Geneva, quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
    Search for more papers by this author
    • These authors contributed equally to this work.

  • Andrew Callan-Jones,

    1. Institut Curie, Centre de Recherche, Membrane and Cell Functions Group; CNRS UMR168, Physico-Chimie Curie; Université Pierre et Marie Curie, 26 rue d’Ulm, 75248 Paris Cedex 05, France
    2. Current address: CNRS UMR 5207, Laboratoire de Physique Theorique et Astroparticules, Université Montpellier II, 34095 Montpellier Cedex 05, France
    Search for more papers by this author
  • Benoit Sorre,

    1. Institut Curie, Centre de Recherche, Membrane and Cell Functions Group; CNRS UMR168, Physico-Chimie Curie; Université Pierre et Marie Curie, 26 rue d’Ulm, 75248 Paris Cedex 05, France
    2. Institut Curie, Centre de Recherche, Molecular Mechanisms of Intracellular Transport Group, CNRS UMR144, 26 rue d’Ulm, 75248 Paris Cedex 05, France
    Search for more papers by this author
  • Winfried Römer,

    1. Institut Curie, Centre de Recherche, Traffic, Signaling and Delivery Group; CNRS UMR144, 26 rue d’Ulm, 75248 Paris Cedex 05, France
    Search for more papers by this author
  • Ludger Johannes,

    1. Institut Curie, Centre de Recherche, Traffic, Signaling and Delivery Group; CNRS UMR144, 26 rue d’Ulm, 75248 Paris Cedex 05, France
    Search for more papers by this author
  • Gilman E. S. Toombes,

    1. Institut Curie, Centre de Recherche, Membrane and Cell Functions Group; CNRS UMR168, Physico-Chimie Curie; Université Pierre et Marie Curie, 26 rue d’Ulm, 75248 Paris Cedex 05, France
    Search for more papers by this author
    • These authors contributed equally to this work.

  • Patricia Bassereau

    Corresponding author
    1. Institut Curie, Centre de Recherche, Membrane and Cell Functions Group; CNRS UMR168, Physico-Chimie Curie; Université Pierre et Marie Curie, 26 rue d’Ulm, 75248 Paris Cedex 05, France
      Patricia Bassereau, patricia.bassereau@curie.fr
    Search for more papers by this author
    • These authors contributed equally to this work.


Patricia Bassereau, patricia.bassereau@curie.fr

Abstract

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.

Ancillary