Protein driven lipid domain nucleation in biological membranes

TL;DR

This study uses simulations to show that transmembrane proteins can initiate lipid raft formation in membranes and that these rafts hinder protein mobility, shedding light on their biological role.

Contribution

It demonstrates through simulations that transmembrane proteins can nucleate lipid domains and affect protein diffusion, providing insights into lipid raft formation mechanisms.

Findings

Proteins can trigger lipid domain nucleation in membranes.

Lipid rafts hinder the diffusion of transmembrane proteins.

Simulations support the role of proteins in raft stability.

Abstract

Lipid rafts are heterogeneous dynamic lipid domains of the cell membranes that are involved in several biological processes, like protein and lipids specific transport and signaling. Our understanding of lipid raft formation is still limited, due to the transient and elusive nature of these domains {\it in vivo}, in contrast to the stable phase-separated domains observed in artificial membranes. Inspired by experimental findings highlighting the relevance of transmembrane proteins for lipid rafts, we investigate lipid domain nucleation by coarse-grained molecular dynamics and Ising model simulations. We find that the presence of a transmembrane protein can trigger lipid domain nucleation in a flat membrane from an otherwise mixed lipid phase. Furthermore, we study the role of the lipid domain in the diffusion of the protein showing that its mobility is hindered by the presence of the raft. The results of our coarse-grained molecular dynamics and Ising model simulations thus coherently support the important role played by transmembrane proteins in lipid domain formation and stability.