Molecular interactions and function of the HOPS complex

Membrane fusion within the eukaryotic endomembrane system depends on the initial recognition of vesicles by multisubunit tethering complexes by Rab GTPases and subsequent coupling to SNARE-mediated fusion. The vacuolar HOPS complex combines SNARE and Rab-binding in one complex. Here, I will present insights into the molecular organization of the HOPS complex using a combination of biochemical assays and molecular genetics and structural approaches. Our data provide the foundation to understand the molecular mechanism of a tethering complex in membrane fusion.