Required to generate and maintain the structure of the tubular endoplasmic reticulum network and the vacuole (PubMed:25646439, PubMed:32432369). Induces high curvature in membranes and causes membrane tubule formation (Probable). Involved in membrane/vesicle trafficking (PubMed:12427979). Oligomer (PubMed:18442980). Interacts with YIP1 (PubMed:11278413). The short lumenal loops between transmembrane domains 1 and 2 and between transmembrane domains 3 and 4 may impart a wedge-like configuration, thus deforming membranes. Cells have more than three vacuoles with a grape-like assembly. Present with 1759 molecules/cell in log phase SD medium. Belongs to the DP1 family.