Triton X-100 promotes a cholesterol-dependent condensation of the plasma membrane

Mercedes Ingelmo-Torres , Katharina Gaus , Albert Herms , Elena González-Moreno , Adam Kassan , Marta Bosch , Thomas Grewal , Francesc Tebar , Carlos Enrich , Albert Pol (1)

1 UB - Universitat de Barcelona

The molecular components of membrane rafts are frequently defined by the biochemical partitioning into detergent-resistant membranes. In this study, we used a combination of epifluorescence and two-photon microscopy to visualize and quantify whether the detergent insolubility reflects a pre-existing organization of the plasma membrane (PM). We found that treatment of cells with cold Triton X-100 (TX) promotes a profound remodelling of the PM including a rapid rearrangement of 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. Rather than inducing the coalescence of pre-existing domains, the remaining domains after TX treatment appear to be newly formed with a higher degree of condensation than those observed in native membranes. However, when cholesterol was physically complexed 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.

Mots clés: Life Sciences

Mercedes Ingelmo-Torres, Katharina Gaus, Albert Herms, Elena González-Moreno, Adam Kassan, et al.. Triton X-100 promotes a cholesterol-dependent condensation of the plasma membrane. Biochemical Journal, 2009, 420 (3), pp.373-381. ⟨10.1042/BJ20090051⟩. ⟨hal-00479147⟩