Lipid membrane-mediated attractions between curvature inducing objects

TL;DR

This study combines experiments and simulations to quantify membrane-mediated attractions between curvature-inducing objects, revealing that membrane curvature causes significant, scale-independent attractive forces that influence protein and particle organization.

Contribution

It provides the first direct experimental and numerical quantification of membrane curvature-mediated interactions across different length scales.

Findings

Membrane deformations induce attractive forces between particles.

The attraction extends over 2.5 times the particle diameter.

The interaction strength is approximately three times thermal energy (-3.3 kT).

Abstract

The interplay of membrane proteins is vital for many biological processes, such as cellular transport, cell division, and signal transduction between nerve cells. Theoretical considerations have led to the idea that the membrane itself mediates protein self-organization in these processes through minimization of membrane curvature energy. Here, we present a combined experimental and numerical study in which we quantify these interactions directly for the first time. In our experimental model system we control the deformation of a lipid membrane by adhering colloidal particles. Using confocal microscopy, we establish that these membrane deformations cause an attractive interaction force leading to reversible binding. The attraction extends over 2.5 times the particle diameter and has a strength of three times the thermal energy (-3.3 kT). Coarse-grained Monte-Carlo simulations of the system are in excellent agreement with the experimental results and prove that the measured interaction is independent of length scale. Our combined experimental and numerical results reveal membrane curvature as a common physical origin for interactions between any membrane-deforming objects, from nanometre-sized proteins to micrometre-sized particles.