Protein Partitioning into Ordered Membrane Domains: Insights from Simulations

Area of Science:

• Cellular biophysics
• Membrane biology
• Computational biology

Background:

• Cellular membranes organize into distinct domains, like lipid rafts, influencing protein function.
• Understanding protein partitioning into these domains is crucial for cellular processes.
• Current knowledge lacks general principles for protein distribution between membrane domains.

Purpose of the Study:

• To elucidate the general principles governing membrane protein partitioning between coexisting liquid domains.
• To investigate the factors determining the dynamics and energetics of protein partitioning.
• To analyze the behavior of a model transmembrane domain from the linker of activation of T cells.

Main Methods:

• Extensive coarse-grained and atomistic molecular dynamics simulations.
• Potential of mean force calculations.
• Development of conceptual models.

Main Results:

• Protein partitioning is governed by protein-lipid interactions and differential lipid packing.
• Palmitoylation and hydrophobic matching promote partitioning into ordered domains.
• Tight lipid packing in ordered domains disfavors partitioning, creating a balance of forces.

Conclusions:

• Established general principles for protein partitioning between membrane domains.
• Explained protein enrichment at liquid-ordered/liquid-disordered interfaces for a model T cell protein.
• Provided insights into experimental and simulation disparities in membrane protein behavior.