Figure 3.

Membrane remodeling activity by the ESCRT complex. (a) Brief overview of some of the cellular functions of the ESCRT complex in mammalian cells. In all processes, ESCRT-III remodel membranes away from the cytosol. The core remodeling machinery (ESCRT-III) is indicated as a blue spiral. ESCRT-III organizes as circular filaments to stabilize the neck of membranes buds. (b) Atomic force microscopy topographic image of the center of a Snf7 patch assembled on GUV membrane. Image reprinted from Chiaruttini et al.¹¹⁵ with permission from Elsevier. (c) The spiral structure acts as a spring collecting elastic energy which upon release buckles the membrane. (d) 3D surface plot of the atomic force microscopy profile showing lipid bilayer formation on top of the 100-nm-deep invaginated template for negative curvature, which approximates the shape of a nascent HIV-1 bud produced by focused ion beam. Image reproduced from Lee et al.⁸⁷ with permission from Proceedings of the National Academy of Sciences USA. (e) Total internal reflection fluorescence (TIRF) image after 20-min incubation with 400 nM of the human ESCRT-III core subunit CHMP4B-Atto488 (DiD fluorescein used as a blue marker for lipids). Image reproduced from Lee et al.⁸⁷ with permission from Proceedings of the National Academy of Sciences USA. (A color version of this figure is available in the online journal.)