Required for normal vault structure. Vaults are multi-subunit structures that may act as scaffolds for proteins involved in signal transduction. Vaults may also play a role in nucleo-cytoplasmic transport (By similarity). The vault ribonucleoprotein particle is a huge (400 A x 670 A) cage structure of 12.9 MDa. It consists of a dimer of half-vaults, with each half-vault comprising 39 identical major vault protein (MVP) chains, PARP4 and one or more vault RNAs (vRNAs) (By similarity).