Self-induced docking site of a deeply embedded peripheral membrane protein

Area of Science:

• Biophysics
• Molecular Biology
• Membrane Protein Interactions

Background:

• Understanding protein-membrane interactions is crucial for cellular processes.
• C2 domains are key regulators of protein targeting to membranes.
• Cytosolic phospholipase A2 (cPLA2) plays a vital role in inflammatory responses.

Purpose of the Study:

• To investigate the molecular mechanisms of C2 domain targeting to lipid bilayers.
• To elucidate the principles governing the interaction between cPLA2-C2 and phosphatidylcholine membranes.
• To determine the role of calcium ions in mediating protein-lipid interactions.

Main Methods:

• Molecular dynamics (MD) simulations of the cPLA2-C2 domain in a lipid bilayer.
• Utilizing high-resolution crystal structure and electron paramagnetic resonance (EPR) data.
• Simulations performed under constant pressure and temperature (NPT) conditions.

Main Results:

• The cPLA2-C2 domain induced local lipid remodeling for optimal docking.
• A cuplike docking site was formed with a hydrophobic bottom and hydrophilic rim.
• Calcium ions did not directly interact with lipid headgroups; water mediated coordination.
• Protein and lipid interactions were consistent with EPR experimental data.

Conclusions:

• Membrane lipid heterogeneity facilitates protein docking site optimization.
• The study provides a general framework for analyzing protein-lipid interactions using integrated computational and experimental approaches.
• This work advances the understanding of C2 domain-membrane targeting principles.