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. May well act as a vesicular anchor by interacting with the target membrane and holding the vesicular and target membranes in proximity. 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 (Probable). Interacts with MIF. Recycles between the cytosol and the Golgi apparatus during interphase. During interphase, the phosphorylated form is found exclusively in cytosol; the unphosphorylated form is associated with Golgi apparatus membranes. 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 promotes dissociation. Belongs to the VDP/USO1/EDE1 family. Contaminating sequence. Potential poly-A sequence.