SNARE proteins facilitate membrane fusion by forming a complex that brings the membranes into close proximity. There are two main types of SNARE proteins: v-SNAREs, located on vesicles, and t-SNAREs, found on target membranes. When the vesicle approaches its target, these proteins bind together in a zipper-like fashion, pulling the membranes together to enable fusion. This process is essential for the proper delivery of cellular components.