The vault is a ubiquitous and highly conserved ribonucleoprotein particle of approximately 13 mDa of unknown function . This family corresponds to a repeated domain found in the amino terminal half of the major vault protein.
Vaults are the largest ribonucleoprotein particles known, having a mass of approximately 13 MDa. They are multi-subunit structures that may act as scaffolds for proteins involved in signal transduction and may also play a role in nucleo-cytoplasmic transport. Vaults are present in most normal tissues, but are more highly expressed in epithelial cells with secretory and excretory functions, as well as in cells chronically exposed to xenobiotics, such as bronchial cells and cells lining the intestine [PUBMED:16918321]. Overexpression of these proteins is linked with multidrug-resistance in cancer cells.
Casanas A, Querol-Audi J, Guerra P, Pous J, Tanaka H, Tsukihara T, Verdaguer N, Fita I;, Acta Crystallogr D Biol Crystallogr. 2013;69:1054-1061.: New features of vault architecture and dynamics revealed by novel refinement using the deformable elastic network approach. PUBMED:23695250 EPMC:23695250.