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Origin of temperature-independent diffusion in FCS: nonequilibrium lipid flows

Establish whether nonequilibrium flows of lipids in live cell membranes are the origin of the temperature independence observed in fluorescence correlation spectroscopy measurements, by directly linking active cytoskeletal dynamics to measured transport properties.

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Background

From equilibrium molecular simulations and nanoscale analyses, the authors infer that correlated equilibrium flows cannot explain temperature-independent transport. This motivates a hypothesis that active, nonequilibrium dynamics—potentially driven by the cortical actin cytoskeleton—underlie the observed temperature independence in FCS.

They explicitly state this as a conjecture before presenting a lattice model supporting the idea, indicating the need for definitive experimental validation in live-cell contexts.

References

Hence, we conjectured that nonequilibrium flows of lipids must be the origin of $T$-independence in the FCS experiment.

— Self-diffusion is temperature independent on active membranes (2404.10581 - Varma et al., 16 Apr 2024) in Results — Local diffusivity in equilibrium is T-dependent (transition to lattice modeling)