General vesicular transport factor required for intercisternal transport in the Golgi stack; it is required for transcytotic fusion and/or subsequent binding of the vesicles to the target membrane (PubMed:7831323, PubMed:7831324, PubMed:10679020). May well act as a vesicular anchor by interacting with the target membrane and holding the vesicular and target membranes in proximity (PubMed:7831323, PubMed:7831324, PubMed:10679020). Homodimer. Dimerizes by parallel association of the tails, resulting in an elongated structure with two globular head domains side by side, and a long rod-like tail structure (PubMed:7831323). Interacts with MIF (By similarity). Interacts with GM130/GOLGA2; interaction is disrupted upon phosphorylation of GM130/GOLGA2 by CDK1 at the onset of mitosis (PubMed:9150144, PubMed:9753325, PubMed:10744704, PubMed:10769027). Recycles between the cytosol and the Golgi apparatus during interphase. Composed of a globular head, an elongated tail (coiled-coil) and a highly acidic C-terminal domain. Phosphorylated in a cell cycle-specific manner; phosphorylated in interphase but not in mitotic cells. Dephosphorylated protein associates with the Golgi membrane; phosphorylation promostes dissociation (By similarity). Belongs to the VDP/USO1/EDE1 family.