Application of a Free Energy Landscape Approach to Study Tension Dependent Bilayer Tubulation Mediated by Curvature Inducing Proteins

TL;DR

This study uses a free energy landscape approach with Monte Carlo simulations to understand how curvature-inducing proteins cause lipid bilayer membranes to form tubes, revealing the conditions and energy barriers involved.

Contribution

It introduces a continuum framework combined with Monte Carlo simulations to analyze protein-induced membrane tubulation and characterizes the free energy barriers associated with the transition.

Findings

Tubular morphologies form when protein density and curvature-field strength exceed thresholds.

The planar to tubular transition can be modeled by a micellar model.

Free energy barriers increase with membrane tension and protein-membrane interaction strength.

Abstract

We investigate the phenomenon of protein induced tubulation of lipid bilayer membranes within a continuum framework using Monte Carlo simulations coupled with the Widom insertion technique to compute excess chemical potentials. Tubular morphologies are spontaneously formed when the density and the curvature-field strength of the membrane bound proteins exceed their respective thresholds and this transition is marked by a sharp drop in the excess chemical potential. We find that the planar to tubular transition can be described by a micellar model and that the corresponding free energy barrier increases with increase in the curvature-field strength, (i.e. of protein-membrane interactions), and also with increase in membrane tension.