Excitable reaction-diffusion waves of curvature-inducing proteins on deformable membrane tubes

TL;DR

This study uses simulations to explore how excitable reaction-diffusion waves of curvature-inducing proteins deform membrane tubes, revealing complex interactions between wave dynamics and membrane shape changes.

Contribution

It introduces a coarse-grained simulation of tubular membranes with a modified FitzHugh--Nagumo model to study mechanochemical coupling effects.

Findings

Protein waves deform membrane tubes and can induce budding.

Large deformations can erase or alter wave propagation.

Wave speed and shape depend on membrane deformation and protein distribution.

Abstract

Living cells employ excitable reaction-diffusion waves for internal cellular functions, in which curvature-inducing proteins are often involved. However, the role of their mechanochemical coupling is not well understood. Here, we report the membrane deformation induced by the excitable reaction-diffusion waves of curvature-inducing proteins and the alternation in the waves due to the deformation, using a coarse-grained simulation of tubular membranes with a modified FitzHugh--Nagumo model. Protein-propagating waves deform tubular membranes, and large deformations induce budding and erase waves. The wave speed and shape are determined by a combination of membrane deformation and spatial distribution of the curvature-inducing protein. Waves are also undulated in the azimuthal direction depending on the condition. Rotationally symmetric waves locally deform the tubes into a symmetric shape but maintain a straight shape on average. Our simulation method can be applied to other chemical reaction models and used to investigate various biomembrane phenomena.