Which protein family plays a crucial role in regulating vesicle fusion?

SNARE proteins (Soluble NSF Attachment Protein Receptors) are essential for mediating vesicle fusion with target membranes, such as in neurotransmitter release or intracellular trafficking. They form a tight complex that brings the vesicle and target membranes close together, enabling fusion. While GTPases (like Rab proteins) help regulate vesicle docking and targeting, SNAREs directly execute the fusion step.