According to available literature structural domains comprising this superfamily share the structure of the Major Vault Protein repeat. Vaults are one of the largest cytoplasmic ribonucleoprotein particles, found in numerous eukaryotic species. The cellular function carried out by this ribonucleoproteins remains unclear, although roles in multidrug resistance and innate immunity have been suggested PMID:19150846. The primary sequence of MVP consists of seven short sequence repeats of ~55 amino acid residues followed by a central region and a coiled-coil protein association domain, which mediates the interactions between MVP molecules PMID:16373071.