Curvature-coupling dependence of membrane protein diffusion coefficients

TL;DR

This study investigates how the coupling between membrane curvature and protein interactions influences the lateral diffusion of membrane proteins, revealing that curvature-coupling can significantly enhance diffusion coefficients.

Contribution

It introduces stochastic simulations that incorporate membrane fluctuations and curvature interactions, providing new insights into how curvature-coupling affects protein diffusion.

Findings

Curvature-coupling substantially increases diffusion coefficients.

Simulations show smaller diffusion than analytical predictions.

Proteins tend to follow favorable membrane curvatures, reducing force fluctuations.

Abstract

We consider the lateral diffusion of a protein interacting with the curvature of the membrane. The interaction energy is minimized if the particle is at a membrane position with a certain curvature that agrees with the spontaneous curvature of the particle. We employ stochastic simulations that take into account both the thermal fluctuations of the membrane and the diffusive behavior of the particle. In this study we neglect the influence of the particle on the membrane dynamics, thus the membrane dynamics agrees with that of a freely fluctuating membrane. Overall, we find that this curvature-coupling substantially enhances the diffusion coefficient. We compare the ratio of the projected or measured diffusion coefficient and the free intramembrane diffusion coefficient, which is a parameter of the simulations, with analytical results that rely on several approximations. We find that the simulations always lead to a somewhat smaller diffusion coefficient than our analytical approach. A detailed study of the correlations of the forces acting on the particle indicates that the diffusing inclusion tries to follow favorable positions on the membrane, such that forces along the trajectory are on average smaller than they would be for random particle positions.