title: Triton X-100 promotes a cholesterol-dependent condensation of the plasma membrane.
abstract: The molecular components of membrane rafts are frequently defined by their biochemical partitioning into detergent-resistant membranes. In the present study, we used a combination of epifluorescence and two-photon microscopy to visualize and quantify whether this insolubility in detergent reflects a pre-existing organization of the PM (plasma membrane). We found that the treatment of cells with cold TX (Triton X-100) promotes a profound remodelling of the PM, including a rapid rearrangement of the glycosphingolipid GM1 and cholesterol into newly formed structures, only partial solubilization of fluid domains and the formation of condensed domains that cover 51% of the remaining membrane. TX does not appear to induce the coalescence of pre-existing domains; instead, the domains that remain after TX treatment seem to be newly formed with a higher degree of condensation than those observed in native membranes. However, when cholesterol was complexed physically by treatment with a second detergent, such as saponin, cholesterol did not separate into the newly formed structures, condensation of the domains was unaltered, and the relative area corresponding to ordered domains increased to occupy 62% of the remaining membrane. Our results suggest that detergent can be used to enrich ordered domains for biochemical analysis, but that TX treatment alone substantially alters the lateral organization of the PM.
authors.affiliation: Departament de Biologia Cel.lular, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Ingelmo-Torres
authors.forename: Katharina
authors.initials: K
authors.lastname: Gaus
authors.forename: Albert
authors.initials: A
authors.lastname: Herms
authors.forename: Elena
authors.initials: E
authors.lastname: González-Moreno
authors.forename: Adam
authors.initials: A
authors.lastname: Kassan
authors.forename: Marta
authors.initials: M
authors.lastname: Bosch
authors.forename: Thomas
authors.initials: T
authors.lastname: Grewal
authors.forename: Francesc
authors.initials: F
authors.lastname: Tebar
authors.forename: Carlos
authors.initials: C
authors.lastname: Enrich
authors.forename: Albert
authors.initials: A
authors.lastname: Pol
mesh_terms: D000818:Animals; D019556:COS Cells; D051242:Caveolin 1 / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism; D002522:Chlorocebus aethiops; D002784:Cholesterol / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D006028:Glycosphingolipids / Q000378:metabolism; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism; D036641:Microscopy, Fluorescence, Multiphoton; D017830:Octoxynol / Q000494:pharmacology*
chemical_list: D051242:Caveolin 1; D003902:Detergents; D006028:Glycosphingolipids; D017830:Octoxynol; D002784:Cholesterol