Hydrodynamic collective effects of active proteins in biological membranes

TL;DR

This paper investigates how active proteins in biological membranes induce non-thermal lipid flows, leading to enhanced diffusion and passive particle attraction, especially within lipid rafts, through analytical and numerical methods.

Contribution

It provides a detailed analytical and numerical analysis of active protein effects on membrane dynamics, focusing on particle attraction within lipid rafts, which was not previously characterized.

Findings

Passive particles are attracted to active rafts.

Active proteins induce non-thermal lipid flows.

Particles accumulate inside lipid rafts.

Abstract

Lipid bilayers forming biological membranes are known to behave as viscous 2D fluids on submicrometer scales; usually they contain a large number of active protein inclusions. Recently, it has been shown [Proc. Nat. Acad. Sci. USA 112, E3639 (2015)] that such active proteins should in- duce non-thermal fluctuating lipid flows leading to diffusion enhancement and chemotaxis-like drift for passive inclusions in biomembranes. Here, a detailed analytical and numerical investigation of such effects is performed. The attention is focused on the situations when proteins are concentrated within lipid rafts. We demonstrate that passive particles tend to become attracted by active rafts and are accumulated inside them.