Required for vesicle-mediated transport. Catalyzes the fusion of transport vesicles within the Golgi cisternae. Is also required for transport from the endoplasmic reticulum to the Golgi stack. Seems to function as a fusion protein required for the delivery of cargo proteins to all compartments of the Golgi stack independent of vesicle origin. Interaction with AMPAR subunit GRIA2 leads to influence GRIA2 membrane cycling (By similarity). ATP + H2O = ADP + H(+) + phosphate Binds 1 Mg(2+) ion per subunit. Homohexamer. Interacts with GABARAP and GABARAPL2. Interacts with GRIA2. Interacts with PLK2, leading to disrupt the interaction with GRIA2. Interacts with MUSK; may regulate MUSK endocytosis and activity (By similarity). Interacts with CDK16 (By similarity). Phosphorylation at Ser-569 interferes with homohexamerization. The disease may be caused by variants affecting the gene represented in this entry. Belongs to the AAA ATPase family.