Estimating the Kinetic Prefactor for Membrane Tube Fission from Fluctuation Dynamics.

Membrane fission is an essential process in cellular organization, governed by both the free-energy barrier separating the (meta)stable states and a kinetic prefactor that encodes membrane dynamics. While advances in continuum and field-based models have made it possible to calculate free-energy barriers for membrane remodeling, estimating the corresponding rates remains challenging because the dynamical prefactor is difficult to determine. We combine coarse-grained particle simulations with previously computed free-energy landscapes to quantify the relaxation dynamics of fluctuating membrane tubes and extract the kinetic prefactor entering the Kramers rate expression. By analyzing the statistics and temporal correlations of tube-radius fluctuations, we demonstrate explicit scaling relationships between relaxation time, diffusion, and tube geometry, replacing heuristic dimensional estimates with direct measurement. Although demonstrated for membrane tubes, this framework provides a general strategy for connecting equilibrium free-energy calculations to dynamical rate predictions in a wide range of membrane-remodeling processes.