The first identified member of the highly conserved VPS13 (vacuolar protein sorting 13) family of proteins was Soi1 (or Vps13) in Saccharomyces cerevisiae, where it plays an important role in membrane protein trafficking between the trans-Golgi network (TGN) and the prevacuolar compartment (7). Specifically, Vps13 is involved in trafficking the protease Kex2p, a protein involved in intracellular insulin processing after overexpression of the latter in yeast (85). Subsequently, a role for this protein was demonstrated in prospore formation in S. cerevisiae through the regulation of phosphatidylinositol 4-phosphate [PI(4)P] generation and membrane-bending activity (48, 49).