Composition variation and underdamped mechanics near membrane proteins and coats

TL;DR

This paper investigates how membrane proteins influence membrane shape and composition, revealing a transition to underdamped behavior that can promote vesicle formation and affect membrane channel activity, with implications for measuring physical parameters.

Contribution

It uncovers a transition in membrane behavior driven by protein coupling, linking shape, composition, and stability changes to early coat assembly and vesiculation.

Findings

Transition to underdamped spatial variation occurs before membrane instability.

Early coat assembly can be favored by the sign change in thermodynamic energy.

Method proposed to infer physical parameters from membrane behavior.

Abstract

We study the effect of membrane proteins on the shape, composition and thermodynamic stability of the surrounding membrane. When the coupling between membrane composition and curvature is strong enough the nearby composition and shape both undergo a transition from over-damped to under-damped spatial variation, well before the membrane becomes unstable in the bulk. This transition is associated with a change in the sign of the thermodynamic energy and hence has the unusual features that it can favour the early stages of coat assembly necessary for vesiculation (budding), while suppressing the activity of mechanosensitive membrane channels and transporters. Our results also suggest an approach to obtain physical parameters that are otherwise difficult to measure.