Final answer:
In the fusion of identical vesicles, V-SNARE and T-SNARE proteins interact to facilitate membrane fusion, which is critical for processes like forming the cis-Golgi. SNARE complexes are later disassembled for recycling.
Step-by-step explanation:
When two identical vesicles fuse, such as in forming the cis-Golgi, the process is mediated by SNARE proteins. Specifically, V-SNARE proteins on vesicles bind to complementary T-SNARE proteins on receiving membranes to facilitate membrane fusion. During this process, the SNARE proteins coil around each other, pulling the vesicle and target membranes together to force the lipid bilayers into contact, initiating fusion. After fusion, the SNARE complexes are dismantled by regulatory proteins so that the SNAREs can be recycled for future use.