What Mechanisms Enable Phospholipid Bilayer Fusion?

💡 The Answer

• SNARE proteins bring two bilayers into close proximity, overcoming repulsive hydration forces.
• Fusion peptides from viral proteins (e.g., influenza HA) insert into the target bilayer, destabilizing it.
• Calcium ions trigger fusion in synaptic vesicles by binding to synaptotagmin and bridging bilayers.
• The fusion pore then expands, allowing content mixing without bilayer rupture.