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). Expression is highest in brain and enriched in the electric lobe. Closely associated with synaptic vesicles in the nerve terminals of the electric organ.