Anomalous diffusion of proteins in sheared lipid membranes

TL;DR

This study uses molecular dynamics simulations to explore how shear flow affects protein diffusion in lipid membranes, revealing superdiffusive behavior due to chaotic motions caused by hydrophobic mismatch and lipid transport.

Contribution

It demonstrates that shear flow induces superdiffusion of proteins in membranes, a novel insight into membrane dynamics under flow conditions.

Findings

Proteins exhibit superdiffusion under shear flow.

Lipid diffusion remains normal regardless of flow.

Chaotic motions cause superdiffusive behavior.

Abstract

We use coarse grained molecular dynamics simulations to investigate diffusion properties of sheared lipid membranes with embedded transmembrane proteins. In membranes without proteins, we find normal in-plane diffusion of lipids in all flow conditions. Protein embedded membranes behave quite differently: by imposing a simple shear flow and sliding the monolayers of the membrane over each other, the motion of protein clusters becomes strongly superdiffusive in the shear direction. In such a circumstance, subdiffusion regime is predominant perpendicular to the flow. We show that superdiffusion is a result of accelerated chaotic motions of protein--lipid complexes within the membrane voids, which are generated by hydrophobic mismatch or the transport of lipids by proteins.