What role do SNARE proteins play in membrane fusion?

SNARE proteins play a crucial role in the process of membrane fusion, particularly in the context of intracellular vesicular transport. They are responsible for mediating the fusion of transport vesicles with their target membranes. This process is vital for various cellular functions, including the secretion of proteins and the delivery of membrane proteins and lipids to their appropriate locations within the cell.

The mechanism involves the assembly of SNARE proteins from both the vesicle (v-SNAREs) and the target membrane (t-SNAREs). When a vesicle approaches its target membrane, the v-SNAREs and t-SNAREs interact and form a stable SNARE complex. This interaction brings the two membranes close together, facilitating their fusion. Once the membranes are fused, content from the vesicle can be released into the target compartment, while also integrating any membrane components into the target membrane.

In summary, the function of SNARE proteins is fundamental to the specificity and efficiency of intracellular trafficking, ensuring that vesicles deliver their contents accurately to designated locations within the cell.