Required for vacuolar assembly. Acts as component of the HOPS complex that acts during the docking stage of vacuole fusion. HOPS is an effector for the vacuolar Rab GTPase YPT7 and is required for vacuolar SNARE complex assembly. It remains bound to SNARE complexes after vacuole fusion. Component of the HOPS complex which is composed of PEP5, VPS16, PEP3, VPS33, VPS39 and VPS41. HOPS associates with phosphoinositides and the PX domain of VAM7. Interacts with VPS41 and VAM7. Sensitive to high hydrostatic pressure (mechanical stress). Present with 319 molecules/cell in log phase SD medium. Belongs to the VAM6/VPS39 family.