Nonequilibrium fluctuations of lipid membranes by the rotating motor protein F ₁ F ₀ -ATP synthase

Abstract

SignificanceThe shape of biological membranes is constantly remodeled and maintained out of equilibrium by active proteins. The functional capacity of membrane deformation is mainly determined by the mechanical interplay between protein activity and bending elasticity. In our experiments, we find that ATP synthase, a rotating membrane protein that synthesizes the biochemical energy in cells through proton-pumping activity across the membrane, promotes localized nonequilibrium membrane fluctuations when reconstituted in giant lipid vesicles. The large membrane deformations emerge from the pumping action of rotating proteins clustered at specific emplacements in the membrane. Our results pave the way to new experimental realizations to explore the collective effects of rotating ATP synthases and their possible biological implications for biomembrane organization and protein functionality.

Supramolecular zippers elicit interbilayer adhesion of membranes producing cell death

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“…Images were captured with a FASTCAM SA3 camera (Photron, San Diego, CA, USA) using an effective pixel-size of 50 nm × 50 nm at 500 frames per second to provide images with an optimal signal-to-noise ratio (SNR). The GUV contours were automatically tracked at the equatorial plane with a custom-made algorithm [ 18 ]. The description of the normal deformation h in a series of discrete Fourier modes, h ( t ) = Σ (q) h q ( t ) exp.…”

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Unveiling the Active Nature of Living-Membrane Fluctuations and Mechanics

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